Integrated Approach to Risk and Condition (JAIC)

8/11/2019 Integrated Approach to Risk and Condition (JAIC)

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AN INTEGRATED APPROACH TO RISK ASSESSMENTS ANDCONDITION SURVEYS

JOEL TAYLOR

JAIC 44 (2005):127141

Understanding something in just one way is a ratherfragile kind of understanding.. . . you need to under-stand something in at least two different ways to reallyunderstand it. Each way of thinking about somethingstrengthens and deepens each of the other ways ofthinking about it. Understanding something inseveral different ways produces an overall understand-ing that is richer and of a different nature than anyone way of understanding.

Resnick 1994, 103

ABSTRACTThis article discusses the integration ofrisk assessment and collection condition surveys, withreference to the uncertainties inherent in each of thesetwo procedures. While condition surveys provideinformation on a collections immediate condition,riskassessments add predictive aspects on the collectionspotential for deterioration. Looking at probable causesof damage in a condition assessment can provide a linkto the agents of deterioration examined in a risk assess-ment. Combining these two complementary assess-ments can provide useful insights and clarify prioritiesfor the collections management goals.Comparison ofthe advantages and disadvantages of two types of eval-uation processes in visual perception, top-down andbottom-up, are discussed as they apply to the integra-tion of the two assessments. Additionally, the articledescribes the use of an integrated assessment approachfor a survey of the English Heritage collections. Inconclusion, it was found that integrating conditionsurveys with risk assessments could increase theknowledge and understanding of current and futureexpectations of a collection.

TITREUne approche intgre pour lvaluationdes risques et de ltat des collections. RSUM

Cet article traite de lintgration de lvaluation desrisques et de ltat des collections en faisant rfrenceaux incertitudes inhrentes chacun de ces processus.Alors que lvaluation de ltat des collections fournitde linformation sur la situation actuelle dune collec-tion, lvaluation des risques prdit les possibilits dedtrioration dune collection. Examiner les causesprobables de dommage lors dune valuation de ltatdes collections peut permettre de faire des liens entreces causes et les agents de dtrioration considrs aucours dune valuation des risques. Joindre ces deuxvaluations complmentaires peut donner un aperu

utile et aider identifier des priorits afin datteindreles objectifs de gestion de collection. Une comparai-son est faite des avantages et dsavantages des deuxtypes de processus dvaluation relies la perceptionvisuelle, soit directe ou indirecte, tel quils sontappliqus lintgration des ces deux types dvalua-tion. Larticle dcrit aussi lusage dune approchedvaluation intgre pour les collection de EnglishHeritage(Patrimoine dAngleterre). En conclusion,ondmontre quen intgrant une valuation de ltatdes collections avec une valuation des risques, on

peut accrotre la connaissance et la comprhensiondes attentes courantes et futures dune collection.

TITULOEnfoque integrado de las evaluaciones deriesgo y encuestas de condicin. RESUMENEsteartculo discute la integracin de las evaluaciones deriesgo y las encuestas de condicin de colecciones, conreferencia a las incertidumbres propias de cada uno deestos dos procedimientos.Mientras que las encuestas decondicin proveen informacin sobre las condicionesinmediatas de las colecciones, las evaluaciones de riesgole suman aspectos predictivos al potencial de deteriorode las colecciones. Mirar hacia las causas probables dedao en una encuesta de condicin puede proveer unenlace con los agentes de deterioro que se examinan enla evaluacin de riesgo. La combinacin de estas eva-luaciones complementarias puede proveer unacomprensin til y clarificar prioridades para los obje-tivos de gestin de las colecciones. La comparacin delas ventajas y desventajas de los dos tipos de proced-imientos de evaluacin en cuanto a percepcin visual,de arriba a abajo y de abajo hacia arriba, son discutidasen lo referente a su aplicacin para la integracin de lasdos evaluaciones.Adicionalmente, el artculo describe eluso de un enfoque integrado de evaluacin para el

inventario de las colecciones de English Heritage(Patrimonio Ingls). En conclusin, se encontr queintegrando las encuestas de condicin con las eva-luaciones de riesgo,se puede aumentar el conocimientoy el entendimiento de las expectativas actuales y futurasde una coleccin.

TTULOUma Viso Integrada Sobre aValia es deRiscos e Levantamentos do Estado de Colees.RESUMOEste artigo discute a integrao da aval-io de risco e do levantamento do estado de colees,com referncia as incertezas inerentes a cada um destes


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procedimentos. Enquando levantamentos do estado decolees proporcionam informaes sobre a condioimediata de uma coleo, avaliaes de risco adicionamaspectos previsveis sobre o potencial de deteriorao dacoleo.Observando-se as causas provveis de danos nolevantamento do estado da coleo, possvel vincul-las aos agentes de deteriorao examinados na avaliaode risco. Combinando-se estas duas avaliaes comple-mentares possvel obter critrios teis e aclarar prior-idades no gerenciamento das colees. So discutidascomparaes das vantagens e desvantagens destes doistipos de processos de avalia,co na percepo visual, decima para baixo e debaixo para cima, no que se aplica`a integrao das duas avialiaes.Alm disto,este artigodescreve a utilizao de uma avaliao integrada para o

levantamento da condio das colees do EnglishHeritage (Patrimnio Ingls). Finalmente, achou-seque a integrao do levantamento do estado dascolees com a avaliao de risco poderia aumentar oconhecimento e o entendimento de atuais e futurasexpectativas de uma coleo.

1. INTRODUCTION

The growth of risk assessment and r isk-based modelsin preventive conservation has been considerable over

the last 10 years (Waller 2002), making conservationplanning a more rational process (Waller 2003). Riskassessmentthe evaluation of potential damage fromidentified hazards to collectionsis an extremelyuseful concept for preventive conservation and plan-ning because it does not rely on the existence ofdamage to establish priorities for its prevention. Riskmanagementthe generation, selection, and imple-mentation of options to accept, reduce, or changerisksrequires information that has a rational frame-work, such as risk assessment, to evaluate and selectappropriate options for the preservation of cultural

heritage. Waller states that forecast risk, rather thanmeasured damage to cultural property, is the appro-priate measure to manage the preservation functionof a museum. Measurement of collection conditionover time will provide verification (or not) of the effi-cacy of the preservation function but not by itselfprovide sufficient information to monitor or plan thepreservation function (Waller 2002, 102).

Collection condition cannot be used to predict thefuture, but using more than one perspective, such asincluding empirical information about condition, cangive perception of risk greater depth and clarity. For

example, when exposure to a risk is identified but thecollection is stable, or objects are deteriorating withinaccepted levels, resources could be spent on resolvingissues that are not affecting the collection as much asother risks. Although intersurveyor differences may bethe root of some of this discrepancy, the forecasting ofdamage and the behavior of objects can highlightwhere that discrepancy is (regardless of the reason) andillustrate areas that may need further analysis. In somecases, empirical information, such as collection condi-tion, can refine this assessment.Introducing concepts ofperception to risk assessment can help integrate suchinformation.This article looks at visual perception as ananalog to inferring from risk and condition assessments,since it provides more information than any of the

other senses (Eysenck and Keane 2000). Cognitivepsychologists and philosophers of science investigatingdecision making have drawn analogies with the keyprinciples of visual perception (e.g., Tversky andKahneman 1974;Oaksford and Chater 1998;Chalmers1999). However, this article is not intended to be areview of the visual perception field.

2. RISK ASSESSMENTS ANDCOLLECTION CONDITIONSURVEYS

Condition surveys collect preselected kinds of informa-tion about an objects deterioration regardless of its past.Past events cannot always help to predict future ones,however (Waller 2002, 2003). Risk assessments maygive an indication of the environment to which acollection is exposed.Without knowing the collectionscondition,collections management decisions created byassessing risk are not necessarily based on what is affect-ing the collection but on what might affect the collec-tion or what control is not in place.

Waller (2002) maintains that risk management orassessment should not be interpreted on the basis of

collection condition, arguing through the case of astray bomb damaging a collection in a highly unpre-dictable way as evidence (after Crumly 1984). Waller(1994) has divided risks into three separate types,basedon their severity and frequency (fig.1).These risk typesfall into one of two categories when assessing proba-bility of damage to collections (Waller 1994, 2003),referred to as catastrophic and deterministic risksby Ashley-Smith (1999). Collection information maynot inform assessments of catastrophic risks, butevidence of deterministic risks is often created duringa collections exposure to environmental hazards, if


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AN INTEGRATED APPROACH TO RISK ASSESSMENTS AND CONDITIONSURVEYS

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they are damaging the collection.Wallers hypothetical example of a risk assessment

(1999) using pollutants did not involve assessment ofcondition or stability, although the probability ofdamage was considered to be certain (probability of1) for all the pollutants assessed (Waller 1999). Thiscertainty of damage is the case for all type 2 and type3 risks (Waller 2003).

Inferring risk of deterioration from data at anylevel is based on a theoretical framework of environ-mental conditions that are suitable or unsuitable forthe preservation of objects.It is this theoretical frame-work within which risk assessments and conditionsurveys often operate (e.g.,Thomson 1986;Michalski1990, 1994; Erhardt and Mecklenburg 1994; Marcon1997).The information recorded is conceptual, basedon an understanding of how objects deteriorate,usingindicators recognized within the framework to helpmake inferences for collection or risk management.However, Ashley-Smith (2000) points out that thereis not a direct relationship between the potential fordeterioration and actual deterioration. Not usingevidence that a collection might provide means thatthe theoretical framework of deterioration ispreferred over the actual interactions between acollection and its environment.

Risk assessment requires effect to be inferred

from cause in a similar way that condition surveysrequire cause to be inferred from effect. Conditionsurveys can be used to determine past causes fromexisting effects (Keene 1991, 2002) and risk assess-ments forecast possible effects from potential causes(Waller 1994, 2002). Conservators are repeatedlyconfronted by damaged objects and are in a positionto build a formal or anecdotal database relatingcondition to probable cause of deterioration(Ashley-Smith 1997, 123).

As Ashley-Smith (1999) and Waller (2002) state,

condition surveys often record effects rather thanprobable causes, so using condition surveys for

preventive purposes can be difficult, because damagemay have already occurred and not be related tocurrent risks.Taylor and Watkinson (2003) point outthat damage categories do not always reflect a partic-ular hazard or set of hazards. And when the damagerelates to more than one category, the interpretivepossibilities increase and can lead to uncertainty ininterpretation.

However, both kinds of inference are based onthe theoretical framework that has been created forconservation, particularly interactions based on theagents of deterioration set out by Michalski (1990).Condition surveys are backward-looking (Waller2002, 104), yet provide information about actualrather than predicted damage. Risk assessments arespeculative but do not require damage for interpreta-tion. Both are assessments of a situation at a particu-lar point in time.

Looking at the whole history of a collectionscondition does mean that fortune, and objects exis-tences before their museum accession, will beassessed as part of the museums preservation func-tion. However, Keene (2002) states that variouselements contribute to a condition score (fig. 2),including stability, which is related to the visible

interaction of the object with various hazards.Condition surveys can reveal evidence of ongoingdeterioration from deterministic hazards (Johnsen1999), such as RH, visible and UV radiation, andpollutants, as well as objects inherent instability.

Fig. 1.Wallers (1994, 12) diagram categorizing risks in termsof their frequency and severity

Fig. 2. Keenes (Keene 2002, 147) diagram of the elementsinvolved in condition scoring illustrates the different kindsof condition that can be assessed.


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Condition surveys can even be used to show that nodeterioration has occurred, and have been used tojustify existing preventive conservation procedures(Johnsen 1999).

This is not to say that risk assessments do notinvolve looking at the collection, or that conditionsurveys do not involve prediction, but the methodsare not often connected. It is important to knowwhether exposure to a hazard and object conditionare related.Van der Reyden et al. (1996) have usedboth in assessments of drawings in an Angel projectthat created a system of matrices, including use,expo-sure, condition, and risk, to prioritize preservationneeds.This system was developed to give priorities tothe needs of different collections, so no diagnostic

link between the kind of risk and kind of damage wasintended.

Johnsen and Bonde-Johansen (2002) usedcondition surveys and time-weighted preservationindices (TWPI) to determine the most suitable stor-age locations for objects based on life expectancy forplanning, but the survey was not intended to assessrisk.

Other condition assessments involving risk havelooked at risk to single objects rather than to collec-tions (Eden et al. 1998). Risks are often external,especially type 1 risks, such as floods, or very hard-to-

make predictions from single objects, such as environ-mental risks. Assessing risk to objects at anitem-by-item level may be possible for some kinds ofchemical stability, but it is limiting for many risks andobjects and cannot detect future changes or reveal a

complete picture (Waller 2003).In brief, it could be argued that risk assessments

are more suitable for catastrophic, type 1 risks, andcondition surveys for deterministic, type 3 risks.

3.THE CAUSE-EFFECTRELATIONSHIP

Cause-effect relationships in complex museum envi-ronments are by no means direct (Koestler et al. 1994;Ashley-Smith 1999,2000).There are object-environ-ment interactions that may not be immediately visi-ble but are nevertheless destructive, such as loweringof pH and different reaction rates between objects.Assessing effects does not necessarily indicate the

risks a collection faces. Equally, assessing exposuredoes not necessarily indicate consequence.Conditionis difficult to diagnose, and risks may be benign, sointeraction between risks and condition is difficult toestablish.

The presence, or absence, of causes and effectsdoes not tell the whole story. Using one perspectivewill produce different kinds of problems when assess-ing risk or consequence. Kinds of inference that canbe used to characterize a cause-effect relationship forrisk assessments and condition surveys, and theirpotential difficulties, are presented in table 1.

The behavior of objects within given environ-ments does not always conform to the theoreticalframework (Padfield 1994; Ashley-Smith 2000).There are various examples of objects and collectionsthat have deteriorated in an unpredictable way

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Table 1. Kinds of Inference and Their Potential Problems in Preventive Conservation Assessment

Relationship Type of Inference

Problems Associated with Inference

CauseEffect Inductive The cause of deterioration to which objects are exposed may nothave an effect on the objects (Ashley-Smith 2000). All causes wouldbe treated the same regardless of their impact on the collection.

No causeNo effect Deductive Unusual phenomena would not be found, such as mold at moderateRH. Inherently unstable objects may not need an unsuitableenvironment to deteriorate.

EffectCause Inductive There is often more than one cause of deterioration (Koestler et al.1994). Condition data recording effects may not differentiatebetween causes. Past deterioration may also be a problem, since thecause may no longer be present but the effects are visible.

No effectNo cause Deductive The effects may be present but not easily detected, such as anincrease in pH. Because an object or collection has not responded toa risk, it does not mean that relatively new problems or rare,catastrophic risks do not exist.


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(Grzywacz and Tennent 1994; Purewal 1997; Ashley-Smith 2000) and deteriorated within conditions that

had been considered to be acceptable (Johnsen 1994;Keene 1994; Julien 2001) or remained stable inconditions outside acceptable levels (Padfield 1994;Bradley and Thickett 1999;Van Oosten 2002). Thereare also problems such as deterioration not beingevident (Fenn 1995) and observations being subjec-tive for both risk assessment (Waller 1994; Ashley-Smith 1997) and condition surveys (Newey et al.1993;Taylor and Stevenson 1999).

Risk and condition can be related to theseconcepts in terms of expectation and observation. Riskassessment is forecasting the probability of eventsthrough the use of an existing theoretical frameworkof damage to objectsthe expectation of damage.Condition surveys collect visible data to determineproblems relating to collectionsthe observation ofdamage.Perceptions in these assessments are based onour knowledge of deterioration.The experience builtup over time sharpens our perception, but it can alsomean that the information perceived is based on rulescreated from past experiences.

4.TOP-DOWN (INDIRECT) ANDBOTTOM-UP (DIRECT)PROCESSING

Waller (1994, 2003) comments on the uncertaintythat is inherent within risk assessment, noting thatwe do not currently have the knowledge requiredto do this precisely(Waller 1994,12). It is this ambi-guity in expectation and the ambiguity of observa-tion within collection condition surveys (Taylor andStevenson 1999;Taylor and Watkinson 2003) that areimportant to recognize. Using these two techniquestogether to temper each other may reduce theuncertainty.

Visual perception has traditionally been divided

into two contrasting theories: top-down processing, bywhich the mind guides representation of objectsbefore the stimulus is processed, and bottom-upprocessing,by which an array of stimuli determine ourperception. Since their conception, these conflictingtheories have been integrated by various workers(Neisser 1976; Marr 1982) to accommodate theiradvantages and shortcomings. When integrated, therelative contributions of these processes will vary fromsituation to situation (Eysenck and Keane 2000).Theyare affected by the amount of information that can beretrieved from a situation, and by existing knowledge

about the object or space. Top-down processingcreates expectations of the world around us based on

our experience. Bottom-up processing involves themore information-rich data that the world contains.By recording this information into a new framework,an added layer of perception through which the worldis represented, and therefore viewed, lies between theconservator and an understanding of the risks to theircollections. This integration of seemingly opposingapproaches has led to a clearer understanding of visualperception. In terms of condition surveys, it is a wayof creating a framework for interpreting the data. Interms of risk assessments, it is a way of incorporatinginformation-rich aspects of the environment.

4.1 TOP-DOWN PROCESSING

Top-down processing is based on knowledge andbringing knowledge to the perceptual event. Whatwe have perceived in the past affects what we perceivein our present environment. This representation issupplemented by sensory information. Everydayperception is frequently supplemented by what weknow; for example, the shape of an object seen fromonly one angle is afforded a three-dimensional repre-sentation. Perception, as a result, is guided by what

information the perceiver selects (fig. 3). What isimportant for accurate perception, in top-downterms, is context.

Top-down processing has clear parallels with dataused in preventive conservation, since the informa-tion is recorded in predetermined categories based ona theoretical constructthe deterioration of materi-als under certain conditions. Condition survey formsprovide a basic conceptual context for the informa-tion to be processedan expectation to a certainextentbut risk assessment creates an actual frame-

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Fig. 3. The devils fork. The image illustrates the tensionbetween the image presented and the interpretation of itbased on the perceptual rules we use.The illusion is knownat a conceptual level, yet it still deceives.


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work based on this conceptual understanding. Thispoint is pertinent, since the environment to which acollection is exposed at a particular point in time ismuch like an individual percept from which onemust interpret.

Top-down processing describes a process that canbe subjective, in that the information is led by pastexperiences to create explanations, even hypotheses(Gregory 1972, 1974, 1998), of stimuli around them.However, the top-down theory does not provide acomplete picture. For example, top-down processingdoes not account for the similarities between differ-ent perceptions.

4.2 BOTTOM-UP PROCESSING

Bottom-up processing is related to the role of thedata. Here the information being viewed, rather thanthe perceiver, is the starting point of perception.Theprocess is similar to the way condition surveys arepurported to collect data, in which information iscollected and then interpreted. Individual interpreta-tion is not heavily involved in bottom-up processing.Information is not perceived as an abstract image butin its context, so it is very information-rich. However,background knowledge is not considered a significant

factor in bottom-up processing, so the framework forinterpreting data is not well developed.

As condition surveys collect data from an infor-mation-rich environment to be recorded and inter-preted, the snapshot results have much in commonwith bottom-up perception that involves a singlepercept. Since bottom-up theory offers little in terms

of how information is interpreted, it has more incommon with empirical approaches to collectionassessment. The two theories directly conflict onseveral points, which are mentioned in table 2.

5.THEORETICAL INTEGRATION

It is clear that every perceptual situation requires anelement of both types of processing, the proportiondiffering in each situation. Everyday navigationrequires more bottom-up processing, whereas repre-senting concepts requires more top-down processing.Risk assessments and condition surveys involve both,although risk assessment focuses on top-down expec-tation, and condition surveys on bottom-up observa-

tion. Each has advantages and drawbacks.Neisser (1976) offered an example of how the

two theories can be satisfied in his analysis-by-synthesis model (fig. 4). He claims that people do notsee their retinal images but see with the aid of them(Neisser 1968). For each perceptual task, perceiverschoose relevant information from all the informationavailable. The constantly changing environmentaround us is an example of the need to select appro-priate information rather than to perceive allelements of an extremely complex environment withequal importance.

Hypotheses about the perceived objects arecontinually updated with new information, which isstored to increase accuracy of future perceptions.Thisprocess is much like risk assessment being refined byperceptual exploration based on theoretical under-standing.What is brought to the perceptual act is aschema, internal to the perceiver (Neisser 1976),

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Fig. 4. Neissers (1976) analysis-by-synthesis, as represented by Gross (2001, 224)


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nature of Marrs computational theory is a useful wayof understanding how detail and inference can beapplied to perception.

While Marrs (1982) process is fundamentallybottom-up (table 3), the knowledge of the perceiver,or conservator, is required to construct the assessmentand apply the theoretical framework of objectdamage that is used to interpret this information.Theassessment of risk is based on the knowledge of whatto look for, and essentially it is a top-down process. It

requires much more interpretation than simply object

recognition. Marrs autonomous stages of perception,linked by a central function, illustrate how assess-ments can be integrated and independent of eachother.

If conservation assessment methods are to becomplementary, a degree of mutual independence isrequired. Otherwise, one process can be used toprove the efficacy of the other. Basing a conditionsurvey on the results of a risk assessment, or viceversa, may lead to a false confirmation of findings.

The possibility of a conservators pursuing a certain

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Fig. 5. Marrs (1982) computational approach to perception has three autonomous stages that build to create a

detailed, dynamic view of the environment (Eysenck and Keane 2000).

Table 3. Marrs (1982) Computational Theory of Perception

Process Action Data

Primal sketch Features of object/light intensity changes are

detected.

Information from the

environment

21/2-D sketch The shape of the object is represented as it appearsto the perceiver.

Visual system of the perceiver

3-D model A representation of the object is created, based onpast experiences of the visual information.

Knowledge of the perceiver

Note: Each process has a different action and collects different kinds of data, which builds up a sophisticatedview of the perceivers environment.


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line can be extended by the reinforcement of a beliefthrough the accumulation of confirmatory evidence.The correlative nature of surveys makes this a realproblem because the accumulation of confirmatoryevidence will increase this effect (Wason 1960, 1996;Evans 1989).

Risk assessments and condition surveys focus oninterpretation in a number of ways, such as the symp-toms of damage denoting condition, conditiondenoting deterioration, or deterioration denotingexposure to hazards. The concepts here are moresubtle and ambiguous than object recognition.Theyrequire an understanding and interpretation of whatthe stimuli mean, not just recognition of what theyare.This level of understanding requires the additionof knowledge from the perceivera top-downprocess of interpretation. When determining theproblems of a collection from conservation assess-ment records rather than the environment itself, these

problems are highlighted.The more information-richprocesses are removed, and collected data lose thecontextual information.

6. INTEGRATING RISKASSESSMENTS AND CONDITIONSURVEYS

The integration of the collection condition surveywith the risk assessment can be done by adding a listof probable causes of damage, in addition to damagetype, to the condition database. Murray has success-

fully attributed damage to causes in condition surveydesign (Edwards and Murray 2002), and the notionis advocated by Ashley-Smith (1997) when practic-ing conservators are involved. Both the causes andeffects of deterioration to an object are based onrisks, and therefore the relationship betweenhazard and damage can be expressed this way.Establishing a one-to-many database relationshipbetween each hazard and the objects surveyed (fig.6)means that the list of probable causes is the same listas the risks looked for in the risk assessment. As aresult, the visible impact of each risk can be viewed

in terms of collection condition.This link acts as the connecting pathway

between separate assessments, similar to Marrs(1982) theory of perception. The format of riskassessment can be based on Wallers (1999) equationof riskP x FS x E x LVin which scores allowlocations, collections, and risks to be compared andgiven priorities, where P is probability of damage, FSis the fraction of the collection susceptible todamage, E is the extent of damage, and LV theexpected loss of value. Wallers Loss of Value(Waller 1999) is, of course,expected loss from whichthe condition is the result.

This simple method allows probable causes ofdamage to be related to actual risks, so an immediateidea of which deterministic risks are having an impacton the collection can be established. It is not alwayspossible to precisely determine causes of deteriora-tion, and there may well be more than one (Koestler

et al. 1994; Ashley-Smith 1999, 2000), so severalcauses can be added to the object section. Themethod consequently addresses the problem associ-ated with cause-effect relationships mentioned intable 1. Risks need to be designated one category inassessment to reduce potential for the same risk to berecorded twice (Waller 2003). This connection tovarious possible causes of deterioration offers aninsight into synergistic effects of risks to collections.

Using a one-to-many relationship, the connec-tion is logically valid. The fact that different causesmay be attributable to a given effect is acknowledged

in this relationship. The problems associated withinference of cause from effect, mentioned in table 1,are reduced.

Taylor and Watkinson (2003) point out that thedifference in deterioration mechanisms for differentmaterials can be helpful. Causes attributed erro-neously for one material would not be recorded forother materials. For example, possible causes ofdiscolored paper may be high temperature, high RH,external pollutants, inherent instability, or a combina-tion of these. Metalwork may indicate that corrosionis present, and high RH the cause, stone may show

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Fig. 6.The one-to-many database relationship that links the independent processes


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salt efflorescence, and wood may show dimensionalchange or mold. The real causes are drawn out

because of these differences in effect. Therefore, theimpact of recording any erroneous causes will belimited to particular types of material, where realcauses would be consistent among different materials.The attribution of these causes is something thatwould be consistent in a risk assessment but not in acondition survey.

For preventive conservation, however, not alldamage provides useful information. As mentionedearlier, damage that took place before an objectentered a museum does little to indicate the effect ofits present environment. Damage that clearly relates

to past environments, such as broken archaeologicalceramics, should be omitted,as it does not determineif an institution is succeeding in its basic duty topreserve collections (Keene 2002, 139). Conditionscoring is similar to that of Keenes stability,although it is not predicting the rate at which anobject is likely to deteriorate (Keene 2002, 147).Stability is the forecast of risk to single objectsrather than to the whole collection from risk expo-sure, and it overlaps with the risk assessment. Waller(2003) points out problems with this approach, usingan example of contamination from old treatmentmethods not indicating contamination from futuretreatment methods. Such damage may indicate agreater instability of treated objects to environmen-tal risks but cannot help forecast future treatments. Itis intended that only risk assessments look at forecastdamage, and condition surveys look at existingeffects. Only damage that can be observed, ratherthan used for forecasting, should be recorded.Present condition is suitable for many type 3 risks,and recent damage is suitable for risks such ashandling and pests. Evidence of damage from knownhazards is important for the overall assessment.Inherent object instability, such as salt efflorescence

from buried ceramics or yellowing from poorlyprocessed cellulose nitrate negatives, should be iden-tified because it has implications for preventiveconservation decisions. The worse the kind ofdamage identified, the more indicative of a threatto the collection. For example, high RH mightfacilitate corrosion that could be a threat, in thecase of hematite, or comparatively benign, in thecase of patina.

Surveying condition must take into accountrecent movements of objects and factors that mightcreate discrepancies between assessments of risk and

condition. Existing damage is sometimes hard toattribute to particular risks. An example is UV and

visible radiation,where fading could have taken placeat any time. However, the circumstances around anobject, such as being in a box or on open display andfaded only in parts where the object is exposed todisplay lighting, will allow one to make a judgment.There may be occasions when a risk is not present atall (Waller 2003), which will inform the conditionsurvey in terms of identifying past damage. Asmentioned earlier, some damage types are easy toomit, and odd occurrences are reduced by using alarge sample of objects. Having to consider severalpossible causes of deterioration means that any corre-

lation of risk and condition is not direct, but thiscorrelation is not always the case in reality either(Ashley-Smith 2000),and the consideration of severalpossible causes makes the determination of synergis-tic effects easier.

Discrepancy between risk and condition does notnecessarily mean that one or the other is correct, butit allows expectation and observation to be integratedto focus on any uncertainty, whether that is due toassessment or object behavior. Cognitively, addressingsuch discrepancies increases performance in real-lifereasoning situations (Dunbar 1993).

The relationship between risk and conditiondoes change with the type of risk, but all risks have aconnection to condition at some level.All interpreta-tion is clearly based on the relationship betweenhazard and damage. The strongest relationship is, ofcourse,with deterministic risks, but all kinds of recentdamage can help refine present or future assessments.Table 4 illustrates the different relationships thatdifferent types of risk have with condition.The rela-tionship is stronger between type 3 risks and condi-tion surveys, but risk assessments are well suited totype 1 risks. Corroboration between a risk assessmentand condition survey indicates both exposure and

consequenceof risk. Lack of corroboration may bedue to a number of reasons, such as damage that hasbeen over- or underestimated, risk that has beenover- or underestimated, a lack of visible effects, ordamage occurring outside expected bands of preser-vation or not occurring in conditions expected topromote deterioration.

7. ENGLISH HERITAGE APPROACH

This concept has since provided the theoreticalunderpinning for a conservation assessment

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currently being carried out by English Heritage forits 134 properties containing collections. The

conservation assessment is an application of therisk assessmentcondition survey concept described,and carried out by the Collections ConservationTeam.

This process started in May 2003 and is ongo-ing. A desire to consistently prioritize the differentpreventive actions over a broad range of properties,as well as evidence that the collections neededpreservation, was required. These assessments areoften the only time that conservators can systemati-cally examine sites and collections spread across thecountry.

The Collections Conservation Team is small, witha large number of collections,and is mostly concernedwith preventive conservation.The conservation assess-ment is intended to provide a solutions-basedapproach to collections management. Given thenumber of locations, the Collections ConservationTeam had already built up a range of activities such astraining and collections care systems for site staff touse. The direction of these programs and otherpreventive conservation activities were to be estab-lished by risk management.

The possibility of mitigating risks that are not a

threat to the collection, when those resources can bespent elsewhere, was considered, as well as the possi-bility that collections are vulnerable to environmentsthat appear to be suitable.

Because similar information was required for thetwo processes, such as the kind of collection, details ofthe location,and the value of the collection, the inte-gration of the assessments had the benefit of the sameinformation being useful to both processes andcollected only once. The process carried out the

collection condition survey first. Surveying collectioncondition also helped to refine estimations of the

kinds and quantities of materials present in certainlocations.1 Location notes were written as well, toprovide more detail and help with the mitigation ofidentified risks. Environmental information was notreadily available in all of the 134 sites, so the riskassessment was sometimes difficult, but it could berefined because of the collection condition surveysystem.

There was often evidence of hazards that did notsignificantly contribute to an objects deterioration.In practice, it was determined that causes of deterio-ration should be regarded as major or minor and

treated separately.The condition grade was attr ibutedto the major causes of deterioration, if any, and minorcauses were not included when more significantdamage was present.

The risks chosen were tailored to the solutions-based approach of the team. As a result, display andstorage materials were looked at as a risk, and disas-ters were categorized as one overall risk, since disas-ter prevention and training are carried out at the sametime. Inherent deterioration of objects was an addedrisk, since object deterioration and lack of exposuremay indicate that the objects themselves are unstable,

and this factor would affect the selection of optionsfor mitigation and explain the possibility of deterio-ration in benign environments.

The assessment of risk involves two scoresonethat assesses probability, the fraction susceptible andloss, based on Wallers (1999) magnitude of r isk, and asecond that includes curatorial value.2 The risk to thecollections can be related to condition without thevalue of the collections influencing this comparison.The overall risk score could be used to make deci-

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Table 4. The Relationship Between Condition Data and Risk

Risk Type Relationship to Condition Data

Type 3 risks Condition data can falsify and corroborate forecasted risk of deterministic, type 3risks.

Type 2 risks Condition data can verify the existence of certain type 2 risks, such as pestinfestations and poor handling, but cannot discount the possibility of futureoccurrences.

Type 1 risks There is little relationship between type 1 risks and condition assessment at anearly stage, but as Ashley-Smith (1999) and Waller (2002) point out, continuedassessment of object damage can lead to refined judgements of risk in the future(and assess the predictive validity of the forecasted risk).

Note: The relationship changes with the type of risk, the clearest association being with deterministic, type 3risks, based on Wallers (1994) risk typology from figure 1.


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sions based on the value of the collections.The scor-ing can be done using Wallers (2003) system but itwas altered for the teams purposes.

Current results indicate that there is a differencebetween risk scores and condition scores for all typesof risk, as well as correlation of risk scores and exist-ing damage.

8. CONCLUSION

Risk assessments and condition surveys are bothvaluable tools for the conservator, which aid plan-ning and direction of resources.These complemen-tary techniques have something to offer each otherin terms of interpreting and planning for preventive

conservation issues, as well as understanding collec-tion deterioration in terms of synergistic factors.The problems of inferring a relationship betweenrisks and collection condition are manifold, but theintegration of risk assessments and condition datacan help reduce some of these problems by thecreation of a relationship between these assess-ments.The field of visual perception illustrates thesimilarities and differences between expected andobservable deterioration and how seeminglyconflicting approaches have been integrated. Bydoing this, potential problems of both can be

reduced, and the data of each given greater contextand meaning.

Basing judgments about mitigation on empiricalevidence, where it exists, allows the conservator toallocate resources effectively and avoid over- andunderestimation of risks, discussed by Waller (2003).Also, the synergistic effects of various hazards mayalso be recognized, since there will be a connectionbetween the kinds of risk and the kinds of damage.This connection does not exist in either of the indi-vidual methods.

Risk assessment gives condition data a framework

for interpretation that provides meaning and contextto observation. Condition surveys alone have a verylimited predictive value (Waller 2002, 2003), and riskassessment provides thatindependent of pastdamage that may affect the survey.

Decisions based on risk assessment have thebenefit of projection that Waller (2002) advocates,andmany potential difficulties of projecting deteriorationfrom past damage alone are avoided. Judgmentscannot be evaluated entirely by outcomes, as Waller(2002) points out, but collection condition does havea role to play in assessing all types of risk.

ACKNOWLEDGMENTS

Gratitude goes to Amber Xavier-Rowe and ClaireSmith (English Heritage) for their application ofthese ideas, discussions, and development of the data-base; Frances Halahan, Jennifer Dinsmore, and SophieBudden (Halahan Associates) for carrying out theassessments and discussions;David Watkinson (CardiffUniversity) and Jonathan Ashley-Smith for discus-sions and comments on drafts; May Cassar (UCL,Centre for Sustainable Heritage) and Dermot Taylorand Geraldine Taylor for comments on drafts; and theeditorial team for their comments.

NOTES

1.The process of using the condition survey to refineestimates of material types was devised by HalahanAssociates while carrying out the English Heritageaudit.2. Discussion with Claire Smith, senior collectionsconservator, was the basis for demarcating betweenrisk scores with and without value. Risk scores withvalue determine the overall priority for theCollections Conservation Team; risk scores withoutvalue determine the projected deterioration of acollection from a given risk.

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JOEL TAYLOR graduated from Cardiff Universitywith a BS in archaeological conservation in 1996. He

has had an interest in collection surveys since then,conducting research in this field as an undergraduate,for which he won the Jerwood Foundation StudentConservator of the Year award in the UnitedKingdom. He has continued this interest, now read-ing part-time for a PhD. He worked as a housekeeperand objects conservator in the Museum of Welsh Life(National Museums and Galleries of Wales) beforejoining English Heritage in 1999 as its first environ-mental management intern, then collections conser-vator and senior collections conservator. He nowworks as a research fellow at the University CollegeLondon (UCL) Centre for Sustainable Heritage.Address: Centre for Sustainable Heritage, BartlettSchool of Graduate Studies, University CollegeLondon, Gower Street, London,WC1E 6BT, UK. e-mail: [email protected]

Received for review on January 30, 2004. Acceptedfor publication on May 4, 2005.

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Integrated Approach to Risk and Condition (JAIC)