Types of Research Designs RS Mehta

TYPES OF RESEARCH &

RESEARCH DESIGNS

1Dr. R S Mehta, MSND, BPKIHS

Types of Study Design: • There is no best type of study design

• The context, assumptions, paradigms and perspectives decide the type of research methodology

Dr. R S Mehta, MSND, BPKIHS 2

How to Choose a Research Design

3

• Does it adequately test the hypothesis?• Does it identify & control extraneous factors?• Are results generalizable?• Can the hypothesis be rejected or retained

via statistical means?• Is the design efficient in using available

resources?

Dr. R S Mehta, MSND, BPKIHS

Selecting a Research Design

1. Level of knowledge2. Nature of the research phenomenon3. Nature of the research purpose4. Ethical considerations5. Feasibility6. Validity and availability of data7. Precision8. Cost


5

1. Define the problem ( Characteristics) 2. Specify the objectives (Hypothesis) 3. Select design or type of study 4. Select study population 5. Collect data 6. Analyze data 7. Determine conclusions

Anatomy of Research



Select design or type of study

Types of ResearchFrom the view point of

ApplicationPure

Research

Applied Research

ObjectivesExploratory Research

Descriptive Research

Correlation Research

Explanatory Research

Type of Information

SoughtQuantitative Research

Qualitative Research


8

TYPE OF STUDIES Observational

1. Correlational study

2. Case reports and case series

3. Cross sectional survey

4. Case-control study

5. Cohort study Experimental

1. Community trials

2. Clinical trials – individuals Dr. R S Mehta, MSND, BPKIHS

Study Designs

9

1. Descriptive Studies2. Cross-Sectional Studies3. Cohort Study4. Case Control5. Randomized Controlled Trials6. Survey Research


Critical Thinking Decision Path: Non-experimental Design Choice


Health Sciences and Nursing ResearchNon-interventional Interventional

Explorative

Descriptive Analytical

Pre-experimental

Quasi-experimenta

l

True-Experiment

- Case study- Cross-

sectional- Longitudinal- Etc.

- Cross-sectional

- Case control

- Cohort - Etc

- CRD- RBD- FD- etc

11Note: CRD-complete random design, RBD-random block design, FD- factorial

designDr. R S Mehta, MSND, BPKIHS

4 Types of Research• Basic research• Applied research• Action research• Evaluation research


Basic Research• Also known as fundamental research

(sometimes pure research) is research carried out to increase understanding of fundamental principles.

• Many times the end results have no direct or immediate commercial benefits

• Basic research can be thought of as arising out of curiosity.

• However, in the long term it is the basis for many commercial products and applied research.

• Basic research is mainly carried out by universities 13Dr. R S Mehta, MSND, BPKIHS

http://en.wikipedia.org/wiki/Research

http://en.wikipedia.org/wiki/Curiosity

http://en.wikipedia.org/wiki/Applied_research

Applied Research• Concern with addressing problem of the world

as they are perceived by participants, organization or group of people

• Action oriented and aims to assess, describe, document or inform people concerned about the phenomenon under investigation

• Findings are intended to have immediate and practical value

• In the field of education, policy, evaluation and contract are all examples of applied research


Action ResearchAction Research is simply a form of self-reflective enquiry undertaken by participants in social situations in order to improve the rationality and justice of their own practices, their understanding of these practices, and the situations in which these practices are carried out.

Wilf Carr and Stephen Kemmis (1986)


Evaluation research• Major concern is practical application• Tends to be viewed as an isolated case study

though the methodologies may be transferable• Rooted in values and politics• Is immediately prescriptive based upon logic and

experience• Reports are written for implementers, users and

other interested people• The extent of dissemination is controlled by

sponsor16Dr. R S Mehta, MSND, BPKIHS

RESEARCH DESIGNSQUANTITATIVE QUALITATIVE

• Experimental study• Quasi-experimental• Survey study• Correlational study

• Ethnography• Case study• Historical study


Types of Study Design: Details


1. Descriptive Studies:

Person, Place and Time


Descriptive Epidemiology

• Includes activities related to characterizing the distribution of diseases within a population

20

• Concerns activities related to identifying possible causes for the occurrence of diseases


Descriptive Epidemiology

21

PERSON

PLACE

TIME

Think of this as the standard dimensions used to track the occurrence of a disease.


Descriptive Research Design:–Describe facts–Discover new facts–Not invent new theory and methods–Largest effort given on data

collection– It answers questions: satisfy

curiosity–Solve problems


2. Cross-Sectional Studies


Features of C-S Studies

24

• Snapshot in time–e.g. - cholesterol measurement and

ECG measured at same time• Determines prevalence at a point in

time• Therefore, C-S is a prevalence study


Advantages of C-S Studies

25

• Short term• Fewer resources required• Less statistical analysis• More easily controlled• Design less complex


Advantages of C-S Studies (Cont.)

26

• Provide relationship between attributes of disease and characteristics of various groups, e.g. elderly group

• Data is useful for planning of health services and medical programs


Disadvantages of C-S Studies

27

• Represent only those who are surveyed• Identify prevalence, not incidence

necessarily–excludes cases that died before study

was done• Show association with survival - not risk of

development


Disadvantages of C-S Studies (cont.)

28

• People who are ill may not show up for survey -*Healthy Person Effect

• Often, not possible to establish temporal relationship between exposure and onset–e.g. does high cholesterol precede CHD?

• Not too effective if disease levels are low, as difficult to establish a causal relationship


Design of a C-S Study


Design of a C-S study (Cont.)


Cross-Sectional Study

31

inelig ible

phys ically active&

C H D

phys ically ac tive&

no C H D

phys ically inac tive&

C H D

phys ically inactive&

no C H D

partic ipation no partic ipation

eligible

F arm ers


Cross-Sectional Study

32

Disease

Exposure yes no total

yes a b a + b

no c d c + d


3. Cohort Study


34

Group by common characteristicsStart with a group of subjects who lack a positive history of the outcome of interest yet are at risk for it (cohort). Think of going from cause to effect.

The exposure of interest is determined for each member of the cohort and the group is followed to document incidence in the exposed and non-exposed members.

Cohort Studies


When is a cohort study warranted?

35

• When good evidence suggests an association of a disease with a certain exposure or exposures.


36

Changes and variation in the disease or health status of a study population as the study group moves through time.

“Generation effect”

Cohort Effect


37

• Prospective (concurrent)

• Retrospective (historical)

• Restricted (restricted exposures)

Types of Cohort Studies


38

Types of Cohort Studies

Prospective – cohort characterized by determination of exposure levels (exposed vs. not exposed) at baseline (present) and followed for occurrence of disease in future

Groups move through time as they age Retrospective - makes use of historical data to determine exposure level at some baseline in the past and then determine subsequent disease status in the present.Restricted - limited exposure, narrow behavior (e.g. military)


Prospective Studies

39

• Also called– longitudinal– concurrent– incidence studies

• Looking into the future• Example:

Study of coronary heart disease (CHD)


40

The essential characteristic in the design of cohort studies is the comparison of outcome in an exposed group and a nonexposed group (or a group with a certain characteristic and a group w/o that characteristic). A study population can be chosen by selecting

groups for inclusion in the study on the basis of whether or not they were exposed

Design of a Cohort Experiment


41

There are two basic ways to generate cohort groups.

Select a cohort (defined population) BEFORE any of its members become exposed or before the exposures are identified.

Select a cohort on the basis of some factor (e.g., where they live) and take histories (e.g., blood tests) on the entire population to separate into exposed and non-exposed groups.

Regardless of which selection approach is used, we are comparing exposed and non-exposed persons.

Selection of Cohort Groups


42

Design of a Cohort Experiment


43

Design of a Prospective Cohort Experiment

Major problem with a prospective cohort design is that the cohort must be followed up for a long period of time.


Data Gathering

44

• Person - to - person• Drop off questionnaire• Mailed to people• Telephone interview• Newsletter or magazine


Potential Biases in Cohort Studies

45

• Information bias• Bias in estimation of the outcome• Bias from non-response • Bias from losses to follow-up• Analytic bias


Advantages of Prospective Cohort Studies

46

• Large sample sizes• Certain diseases or risk factors targeted• Can be used to prove cause-effect• Assess magnitude of risk• Baseline of rates• Number and proportion of cases that can be

prevented


Advantages of Prospective Studies (cont’d)

47

• Completeness and accuracy• Opportunity to avoid condition being

studied• Quality of data is high• Considers seasonal and other variations

over a long period• Tracks effects of aging process


Disadvantages of Prospective Cohort Studies

48

• Large study populations required– not easy to find subjects

• Expensive• Unpredictable variables• Results not extrapolated to general population• Study results are limited• Time consuming/results are delayed• Requires rigid design and conditions


Disadvantages of Prospective Studies (cont’d)

49

• Subjects lost over time (dropouts)• Costs are high• Logistically demanding• Maintaining quality, validity, accuracy

and reliability can be a problem


Cohort/ Longitudinal Studies

50

Design

Sample Of Population

High Exposure

Medium Exposure

Low Exposure

No Exposure

Outcome

Outcome

Outcome

OutcomeDr. R S Mehta, MSND, BPKIHS

51

Prospective Cohort Design


52

Retrospective Cohort Design


COHORT STUDY

53

Source Population Cases(= Exposed, =Unexposed) (□= Exposed, ■=Unexposed)

■ □ □ ■ ■ ■ □ ■ □ ■ □ □ ■ □ ■ □


4. Case Control Study


CASE-CONTROL STUDIESSOME KEY POINTS

55

• Frequently used study design• Participants selected on the basis of whether or

not they are DISEASED (remember in a cohort study participants are selected based on exposure status)

• Those who are diseased are called CASES.• Those who are not diseased are called

CONTROLS.


Case-Control Study

56

inelig ible

exposed un exposed

bad ou tcom e(cases)

exposed unexposed

good ou tcom e(con trols)

partic ipation no partic ipation

eligib le

S ou rce P opu lation


57

Case-Control Design


Case-Control Design

58

Subjects With Outcome of Interest

Design

Appropriate Control Group Without Outcome Of Interest

Measure factors

Compare factors


Case-Control Studies

59

dcNo

baYes

Present

Outcome

Absent

Exposure to intervention or causal factor

Direction

Of

Sampling

Results


Case- Control Design: Advantages

60

1. Valuable for studying rare conditions.2. Short duration3. Relatively inexpensive4. Relatively smaller sample needed5. Yields odd ratio (usually a good

approximation of relative risk)


Case- Control Studies: Disadvantages

61

1. Limited to one outcome variable2. Potential bias from selection of cases and

controls3. Does not establish sequence of events4. Potential bias in measuring exposure5. Potential survivor bias6. Does not yield absolute risk estimates.


PAST PRESENT

Exposure recall Cases & ControlsSelected

Example: lung cancer cases and non-cancerous controls recall past exposure to cigarette smoke

Because participants are selected on the basis of disease, exposures for ALL PARTICIPANTS are obtained RETROSPECTIVELY…………..


SELECTION OF CASES

63

• Decide on a specific case definition based on a medically diagnosed condition.When diagnosis relies on subjective assessment case definition

will be less precise.• Must consider what criteria will confirm the case definition:

Lung cancer confirmed by biopsyOsteoporosis confirmed by bone density measurementsStudying mild forms of a disease results in largest possible case

group but may include non-cases (misclassification)Studying severe forms of a disease decrease the probability of

misclassification


SELECTION OF CONTROLS

64

• Controls should be representative of the referent population from which cases are selected (i.e. comparable)–Controls should have the potential to become

cases; Controls should also be candidates for having the disease of interest


SELECTION OF CONTROLS (2)

65

• Different Types of Controls………

–Population controls• Randomly selected individuals from the

population like RDD (random digit dialing)

–Neighborhood controls• Individuals that live in the same

neighborhoods as casesDr. R S Mehta, MSND, BPKIHS


66

–Friends controls• best friends of cases• spouses or siblings of cases

–Hospital controls• Individuals at the same hospital with

cases



67

• The investigator can elect to use more than one TYPE of control for each case……. When there is no ONE group similar enough to cases.

EXAMPLE: A particular leukemia case may have both a neighborhood control (similar to case in terms of environment) and a sibling control (similar to case in terms of genetic background).


Cases & Controls

68

• For each CASE in the study, a control is selected• How many controls should be selected per case?

–1:1 is usual– Increasing the ratio of controls to cases increases

the precision and efficiency of the analysis– It also increases the cost to undertake the study


MATCHING

69

• CHARACTERISTICS OFTEN USED

–age–gender–body mass index (weight / height2)–smoking status–marital status


MATCHING (2)

70

• GROUP MATCHING• Based on proportions• Idea is to select a control group with a certain

characteristic identical to cases in the same proportion as it appeared in cases.

Example: If 25% of cases in your study smoke you would select a control population that included 25% smokers.


GROUP MATCHING EXAMPLE

CASE POPULATION CONTROL POPULATION

Smokers

Non-Smokers

Smokers

Non-Smokers


MATCHING (3)

72

2) INDIVIDUAL MATCHING (matched pairs)• For every individual case a control is selected who

is identical to the case on certain characteristics.

Example: If your first case is a 25 year-old women who smokes then you would find a control who is 25, female and a smoker. So you are matching on age, gender, and smoking status.


MATCHED PAIRS EXAMPLE

73

CASE

CONTROL

CASE

CONTROL


POTENTIAL PROBLEMS WITH MATCHING

74

• It will be difficult to find controls if too many variables are selected for matching.

• Variables used for matching can not be studied as exposures or confounders.

• OVERMATCHING – when variables related to disease are inadvertently matched upon.


Classic 2 x 2 Table for a Case-Control Study if in the POPULATION

75

Disease No Disease

Exposure A B

No Exposure C D

Odds Ratio = A/C = AD B/D BC


Example: Hypothetical data

76

Cases Controls

Exposed 141 133Unexposed 1250 4867

Total 1391 5000

ODDS RATIO = 141 * 4867 = 4.13 133 * 1250Dr. R S Mehta, MSND, BPKIHS

Interpretation of the Odds Ratio…

77

If:OR = 1 then exposure is NOT related to

disease

OR>1 then exposure is POSITIVELY related to

disease

OR<1 then exposure NEGATIVELY related to disease


Interpretation:

78

The odds that those with the outcome had the exposure is 4.13 times greater than those who do not have the outcome


Strengths:

79

1. Quick and inexpensive2. Well-suited to the evaluation of outcomes

with long latent periods3. Optimal for the evaluation of rare diseases4. Can examine multiple etiologic factors for a

single disease


Limitations:

80

1. Cannot directly compute incidence rates of disease

2. Temporal relationship between exposure and disease may be difficult to establish

3. Prone to bias4. Insufficient to evaluate rate exposure


TYPES OF RESEARCH &

RESEARCH DESIGNS


Types of Study Design: • There is no best type of study design

• The context, assumptions, paradigms and perspectives decide the type of research methodology


Health Sciences and Nursing ResearchNon-interventional Interventional

Explorative


Pre-experimental

Quasi-experimenta

l

True-Experiment



- Cross-sectional

- Case control

- Cohort - Etc

- CRD- RBD- FD- etc



5. Randomized Controlled Trials


Randomized Controlled Trials

85

• Similar groups of individuals from same source population are allocated at random to receive or not to receive an intervention, then observed for occurrence of outcome(s).

DESIGN

Subjects with condition of Interest

Experimental Group

Control

Outcome

Outcome


86

A Factorial RCT for Two Studies for the Price of One


RCT– the “gold standard” of research designs.

They thus provide the most convincing evidence of relationship between exposure and effect. Example: • trials of hormone replacement

therapy in menopausal women


Randomized Controlled Trial : Advantages

88

1. Comparability due to randomization and same effect of known and unknown confounders gets eliminated

2. Experiments provide strong evidence of cause and effect.

3. Allows standardization of eligibility criteria, maneuver and outcome assessment.

4. Allows use of statistical methods with few inbuilt assumptions.


Randomized Controlled Trial : Disadvantages

89

1. May be expensive in terms of time, money and people.

2. Many research questions are not suitable due to ethics, likely co-operation or rarity of outcome.

3. To a greater or lesser extent RCT tends to be an artificial situation.


Suitable Study Design

90

Issues Study Design

Diagnosis Cross sectional Therapy RCT (Non-RCT)Prognosis Prospective cohortCause Cohort

Case controlDescription Case Series

Cross Sectional

However, more than one study design can be used to answer any given question of causal association


6. Survey Research


Survey research• Survey research is often used to assess

thoughts, opinions, and feelings• Psychologists and sociologists often use survey

research to analyze behavior, while it is also used to meet the more pragmatic needs of the media, such as, in evaluating political candidates, public health officials, professional organizations, and advertising and marketing directors.

• A survey consists of a predetermined set of questions that is given to a sample.

• Every day you find in TV and Radio?Dr. R S Mehta, MSND, BPKIHS 92

http://en.wikipedia.org/wiki/Psychologists

http://en.wikipedia.org/wiki/Sociologists

http://en.wikipedia.org/w/index.php?title=Political_candidates&action=edit&redlink=1

http://en.wikipedia.org/w/index.php?title=Public_health_officials&action=edit&redlink=1

http://en.wikipedia.org/wiki/Professional_organizations

http://en.wikipedia.org/wiki/Advertising

http://en.wikipedia.org/w/index.php?title=Marketing_directors&action=edit&redlink=1

Survey design: • Evaluative• Comparative• Short-term• Long-term• Longitudinal• Cross-sectional• Cross-cultural


Questions to Ask Before Doing Survey Research

94

• Do you have a clear hypothesis?• Do your questions focus on that

hypothesis?• Will participants answers provide

accurate answers to your questions?• To whom will your results apply?


Planning a Survey

96

• Deciding on a research question• Choosing the format of your questions• Choosing the format of your interview--if

you use an interview• Editing your questions• Sequencing your questions• Refining your survey instrument• Choosing a sampling strategy


Editing Questions: Nine Mistakes to Avoid

97

1. Avoid leading questions

2. Avoid questions that invite the social desirability bias

3. Avoid double-barreled questions

4. Avoid long questions

5. Avoid negations6. Avoid irrelevant

questions7. Avoid poorly

worded response options

8. Avoid big words9. Avoid ambiguous

words & phrases


Survey researchers should carefully construct the order of questions in a questionnaire


7. Case Study• Explores in depth a program, event, activity, process,

or one or more individuals• Bounded (separated out for research) by time, place

and activity• Researcher collects detailed information using a

variety of data collection procedures over a sustained period of time (Stake & Creswell)

• A method of learning about a complex instance based on a comprehensive understanding of that instance obtained by extensive description and analysis of that instance taken as a whole


Case Study/Reports• Detailed presentation of a single case or

handful of cases• Generally report a new or unique finding

• e.g. previous undescribed disease• e.g. unexpected link between diseases• e.g. unexpected new therapeutic effect• e.g. adverse events


Case Series• Experience of a group of patients with a

similar diagnosis• Assesses prevalent disease• Cases may be identified from a single or

multiple sources• Generally report on new/unique

condition• May be only realistic design for rare

disorders101Dr. R S Mehta, MSND, BPKIHS

Case Series• Advantages

• Useful for hypothesis generation• Informative for very rare disease with few

established risk factors• Characterizes averages for disorder

• Disadvantages• Cannot study cause and effect relationships• Cannot assess disease frequency


8. Historical Study• Focuses primarily on the past• Persuing documents of the period• Examining relics (left over)• Interviewing individuals who lived during that time• Reconstruct what happened during that time as

completely as possible• Systematic collection and evaluation of data to

describe, explain, and thereby understand actions or events that occurred in the past

• No manipulation or control of variables103Dr. R S Mehta, MSND, BPKIHS

104

9. Experimental Research Designs


Aim: • The aim of experimental research is to

investigate the possible cause and effect relationship by manipulating one independent variable to influence the other variable in the experimental group and by controlling the other relevant variables and measuring the effects of the manipulation by some statistical means.


106

Experimental Research Triesto Establish Cause and Effect

• Selection of a good theoretical framework• Application of appropriate experimental design• Use of correct statistical model and analysis• Proper selection and control of independent

variables• Appropriate selection and measurement of

dependent variables• Correct interpretation of results


Characteristics or Features of Experimental Design

1. Manipulation2. Control3. Randomization


Experimental Design• Advantages

– Best establishes cause-and-effect relationships

• Disadvantages– Artificiality of experiments– Feasibility– Unethical


Types of Experimental Designs

• True-Experimental (Simple)• Quasi-Experimental• Pre-Experimental


True, Qusi, & Pre- Experimental Study

Randomization, Control and Manipulation

• True exp.: All 3: R C M• Quasi exp.: M + R or C • Pre exp.: M, no R & no C


Steps in Experimental Research• State the research problem• Determine if experimental methods apply• Specify the independent variable(s)• Specify the dependent variable(s)• State the tentative hypotheses• Determine measures to be used• Pause to consider potential success• Identify intervening (extraneous) variables• Formal statement of research hypotheses• Design the experiment• Final estimate of potential success• Conduct the study as planned• Analyze the collected data• Prepare a research report


10. Ex Post Facto Study• Variable of interest is not subject to direct

manipulation but must be chosen after the fact.E.g., Define two groups of people according to a certain characteristic (e.g., history of trauma) and measure how they respond in terms of anxiety to a certain stimulus (e.g., watching violent film).

• Limitation – self-selection bias, cohort effects.


11. Meta Analysis

113

• Combining the results from many studies dealing with the same topic.

• Statistically combines results of existing research to estimate overall size of relation between variables

• Helps in • Developing theory • Identifying research needs, • Establishing validity

• Can replace large-scale research studies• Better than literature reviews


• It is similar to a simple cross-sectional study, in which the subjects are individual studies rather than individual people.

• A review of literature is a meta-analytic review only if it includes quantitative estimation of the magnitude of the effect and its uncertainty (confidence limits).


Meta analysis

Quantitative approach for

systematically combining results of previous research to arrive at conclusions about the body of research.


• Quantitative : numbers• Systematic : methodical• combining: putting together• previous research: what's already done• conclusions: new knowledge


Steps for Conducting A Meta-Analysis

A. Data SourcesB. Study SelectionC. Data AbstractionD. Statistical Analysis



Statistical conceptsThe impact of fish oil consumption on Cardio-vascular diseases

118


Forest plot

119

Advantages of Meta-Analysis

1. Study question specific & narrow2. Data collection comprehensive &

specific3. Study selection based on uniformly

applied criteria4. Data synthesis quantitative


12. Qualitative Research


Choice of Colours

• 1. What colour would you like the most?


2.What do you associate this colour with?Good luckloveConfidenceTruthfulnessLivelyDanger…


3. What is the source of this knowledge?–Own Idea–Own Belief–Own observation–Own experiences –Cultural and Traditional–Books & articles– etc


• Not every thing can be quantified.• Some valuable ideas, opinions,

perceptions, experiences, behaviours, qualities can be described only in words

• These subjective things are shared between people, but the meanings may be distorted in the process of communication and recording.


• Although subjective, these aspects often add richness and depth

• The art of the doctor and the experience of being human are aspects that need a qualitative approach to investigate/research properly.


• Qualitative Research - investigation in which the researcher attempts to understand some larger reality by examining it in a holistic way or by examining components of that reality within their contextual setting.


Qualitative Research• ‘Qualitative Research…involves finding out what

people think, and how they feel - or at any rate, what they say they think and how they say they feel. This kind of information is subjective. It involves feelings and impressions, rather than numbers’

- Bellenger, Bernhardt and Goldstucker, Qualitative Research in Marketing, American Marketing Association


Universal

Specific

Explanatory

Descriptive Subjective

Objective

Universal ------------------------------ SpecificObjective ------------------------------ SubjectiveExplanatory ---------------------------- Descriptive


Characteristics of Qualitative Research

• Purpose is understanding• Oriented toward discovery• Uses subjective data• Extracts meaning from data• Interprets results in context• Focus is holistic


Organizational Structures (Types)

Historical Analysis Ethnography Phenomenology Life History,

Chronology,Historiography

Case Study


Ethnographic Design• Examining a group of individuals in the setting where

they live and work, and in developing a portrait of how they interact

• Describing, analyzing and interpreting a group’s shared patterns of behavior, beliefs and language that develop over time

• Provides a detailed picture of the group, drawing on various sources of information

• Describes the group within its settings, explores themes or issues that develop over time as the group interacts

• Data analysis emphasize on description and explanation rather than quantification and statistical analysis (Atkinson & Hammersley, 1994)


Phenomenology• Definition: “Phenomenology is an

approach which attempts to understand the hidden meanings and the essence of an experience together with how participants make sense of these.” (Grbich 2007, p. 84).

• Strengths: Phenomenology is used to explore, describe, document rich details of people’s experiences, especially changes in feelings and experiences over time.


phenomenology


Qualitative Data Collection Techniques

• In depth Interviewing • Focus Groups • Participant Observations• Ethnographic Studies• Projective Techniques


Analysis Qualitative Data: An Approach

• Categorisation• Unitising data• Recognising relationships and developing

the categories you are using to facilitate this

• Developing and testing hypotheses to reach conclusion


Tools for helping the Analytical Process

Summaries• Should contain the key points that emerge from

undertaking the specific activitySelf Memos• Allow you to make a record of the ideas which

occur to you about any aspect of your research, as you think of them

Researcher Diary


Advantages of Qualitative Research In-depth Examination of Phenomena

(Phenomenological Study) Uses subjective information Not limited to rigidly definable variables Examine complex questions that can be impossible

with quantitative methods Deal with value-laden questions Explore new areas of research Build new theories


Disadvantages of Qualitative Research

Subjectivity leads to procedural problems Replicability is very difficult Researcher bias is built in and unavoidable In-depth, comprehensive approach to

data gathering limits scope Labor intensive, expensive Not understood well by

“classical” researchers


Review: Health Sciences and Nursing ResearchNon-interventional Interventional

Explorative


Pre-experimental

Quasi-experimenta

l

True-Experiment



- Cross-sectional

- Case control

- Cohort - Etc

- CRD- RBD- FD- etc



Cont’d


Relative strength of various study designs (based on level of evidence for a cause &

effect relationship)

142

Strength Design Strong Clinical trial

Cohort study Case control study Cross sectional Case series

Weak Case report


Websites, Search Engine, and address of Journals

• www.pubmed.com• www.google.com• www.yahoo.com• www.msn.com• www.rn.com• www.who.int (WHO website)• www.randamization.com• www.tnaionline.org (TNAI Journal) • www.hellis.org (NHRC library site)• www.kumj.com.np• www.nhrc.org.np• www.uicc.org (cancer website)• www.unaids.org (HIV/AIDS website)• www.ncasc.org.np (HIV/AIDS website)• www.healthinternetwork.org (HINARI: needs password)• www.blackwell-synergy.com (need passwords)• www.doaj.org (free online journal)


http://www.pubmed.com/

http://www.google.com/

http://www.yahoo.com/

http://www.msn.com/

http://www.rn.com/

http://www.who.int/

http://www.randamization.com/

http://www.tnaionline.org/

http://www.hellis.org/

http://www.kumj.com.np/

http://www.nhrc.org.np/

http://www.uicc.org/

http://www.unaids.org/

http://www.ncasc.org.np/

http://www.healthinternetwork.org/

http://www.blackwell-synergy.com/

http://www.doaj.org/

Some Popular Resource Sites for Nurses

• www.delicious.com• www.connotea.org• www.scribd.ocm• www.authorstream• www.zotero.org• www.scratch.mit.edu• www.myebook.com• www.forvo.com


http://www.delicious.com/

http://www.connotea.org/

http://www.scribd.ocm/

http://www.authorstream/

http://www.zotero.org/

http://www.scratch.mit.edu/

http://www.myebook.com/

http://www.forvo.com/

“The beautiful thing about learning is that nobody can

take it away from you.”

--BB King

Thank-You145


Review: Health Sciences and Nursing ResearchNon-interventional Interventional

Explorative


Pre-experimental

Quasi-experimenta

l

True-Experiment



- Cross-sectional

- Case control

- Cohort - Etc

- CRD- RBD- FD- etc



Cont’d


Relative strength of various study designs (based on level of evidence for a cause &

effect relationship)

148

Strength Design Strong Clinical trial

Cohort study Case control study Cross sectional Case series

Weak Case report


Websites, Search Engine, and address of Journals

• www.pubmed.com• www.google.com• www.yahoo.com• www.msn.com• www.rn.com• www.who.int (WHO website)• www.randamization.com• www.tnaionline.org (TNAI Journal) • www.hellis.org (NHRC library site)• www.kumj.com.np• www.nhrc.org.np• www.uicc.org (cancer website)• www.unaids.org (HIV/AIDS website)• www.ncasc.org.np (HIV/AIDS website)• www.healthinternetwork.org (HINARI: needs password)• www.blackwell-synergy.com (need passwords)• www.doaj.org (free online journal)


http://www.pubmed.com/

http://www.google.com/

http://www.yahoo.com/

http://www.msn.com/

http://www.rn.com/

http://www.who.int/

http://www.randamization.com/

http://www.tnaionline.org/

http://www.hellis.org/

http://www.kumj.com.np/

http://www.nhrc.org.np/

http://www.uicc.org/

http://www.unaids.org/

http://www.ncasc.org.np/

http://www.healthinternetwork.org/

http://www.blackwell-synergy.com/

http://www.doaj.org/

Some Popular Resource Sites for Nurses

• www.delicious.com• www.connotea.org• www.scribd.ocm• www.authorstream• www.zotero.org• www.scratch.mit.edu• www.myebook.com• www.forvo.com


http://www.delicious.com/

http://www.connotea.org/

http://www.scribd.ocm/

http://www.authorstream/

http://www.zotero.org/

http://www.scratch.mit.edu/

http://www.myebook.com/

http://www.forvo.com/

“The beautiful thing about learning is that nobody can

take it away from you.”

--BB King

Thank-You151


Developmental Research Designs

Longitudinal

• Powerful (within subject)

• Time consuming• Attrition• Testing effect

Cross Sectional

• Less time consuming

• Cohorts problem


Research Designs/Approaches

Type Purpose Time frame

Degree of control

Examples

Experi-mental

Test for cause/effect relationships

current High Comparing two types of treatments for anxiety.

Quasi-experi-mental

Test for cause/effect relationships without full control

Current Moderate to high




Degree of control

Examples

Non-experimental - corre-lational

Examine relationship between two variables

Current (cross-sectional) or past

Low to medium

Relationship between studying style and grade point average.

Ex post facto

Examine the effect of past event on current functioning.

Past & current

Low to medium

Relationship between history of child abuse & depression.


Research Designs/ApproachesType Purpose Time

frameDegree of control

Examples

Non-experimental -corre-lational

Examine relat. betw. 2 var. where 1 is measured later.

Future -predictive

Low to moderate

Relat. betw. history of depression & development of cancer.

Cohort-sequen-tial

Examine change in a var. over time in overlapping groups.

Future Low to moderate

How mother-child negativity changed over adolescence.




Degree of control

Examples

Survey Assess opinions or characteristics that exist at a given time.

Current None or low

Voting preferences before an election.

Quali-tative

Discover potential relationships; descriptive.

Past or current

None or Low

People’s experiences of quitting smoking.



Experimental Designs Details


Symbolism for Diagramming Experimental Designs

X = exposure of a group to an experimental treatmentO = observation or measurement of the dependent variable

If multiple observations or measurements are taken, subscripts indicate temporal order – I.e., O1, O2, etc.= random assignment of test units; individuals selected as subjects for the experiment are randomly assigned to the experimental groups

R


Pre-Experimental Designs• Do not adequately control for the problems

associated with loss of external or internal validity

• Cannot be classified as true experiments• Often used in exploratory research• Three Examples of Pre-Experimental Designs

– One-Shot Design– One-Group Pretest-Posttest Design– Static Group Design


One-Shot Design• A.K.A. – after-only design• A single measure is recorded after the

treatment is administered• Study lacks any comparison or control of

extraneous influences• No measure of test units not exposed to the

experimental treatment• May be the only viable choice in taste tests• Diagrammed as: X O1


One-Group Pretest-Posttest Design

• Subjects in the experimental group are measured before and after the treatment is administered.

• No control group• Offers comparison of the same individuals before

and after the treatment (e.g., training)• If time between 1st & 2nd measurements is

extended, may suffer maturation• Can also suffer from history, mortality, and testing

effects• Diagrammed as O1 X O2


Static Group Design• A.K.A., after-only design with control group• Experimental group is measured after being exposed

to the experimental treatment• Control group is measured without having been

exposed to the experimental treatment• No pre-measure is taken• Major weakness is lack of assurance that the groups

were equal on variables of interest prior to the treatment

• Diagrammed as: Experimental Group X O1

Control Group O2 163Dr. R S Mehta, MSND, BPKIHS

Pretest-Posttest Control Group Design

• A.K.A., Before-After with Control• True experimental design• Experimental group tested before and after

treatment exposure• Control group tested at same two times without

exposure to experimental treatment• Includes random assignment to groups• Effect of all extraneous variables assumed to

be the same on both groups• Do run the risk of a testing effect


Pretest-Posttest Control Group Design• Diagrammed as

– Experimental Group: O1 X O2

– Control Group: O3 O4• Effect of the experimental treatment equals

(O2 – O1) -- (O4 – O3) • Example

– 20% brand awareness among subjects before an advertising treatment

– 35% in experimental group & 22% in control group after the treatment

– Treatment effect equals (0.35 – 0.20) – (0.22 – 0.20) = 13%

RR


Posttest-Only Control Group Design

• A.K.A., After-Only with Control• True experimental design• Experimental group tested after treatment exposure• Control group tested at same time without exposure

to experimental treatment• Includes random assignment to groups• Effect of all extraneous variables assumed to be the

same on both groups• Do not run the risk of a testing effect• Use in situations when cannot pretest


Posttest-Only Control Group Design• Diagrammed as

– Experimental Group: X O1

– Control Group: O2

• Effect of the experimental treatment equals(O2 – O1)

• Example– Assume you manufacture an athlete’s foot remedy– Want to demonstrate your product is better than

the competition– Can’t really pretest the effectiveness of the remedy

RR


Solomon Four-Group Design

• True experimental design• Combines pretest-posttest with control

group design and the posttest-only with control group design

• Provides means for controlling the interactive testing effect and other sources of extraneous variation

• Does include random assignment


Solomon Four-Group Design• Diagrammed as

– Experimental Group 1: O1 X O2

– Control Group 1: O3 O4

– Experimental Group 2: X O5

– Control Group 2: O6

• Effect of independent variable (O2 – O4) & (O5 – O6)

• Effect of pretesting (O4 – O6) • Effect of pretesting & measuring (O2 – O5) • Effect of random assignment (O1 – O3)

RR

RR


Quasi-Experimental Designs• More realistic than true experiments• Researchers lacks full control over the

scheduling of experimental treatments or• They are unable to randomize• Includes

– Time Series Design– Multiple Time Series Design

• Same as Time Series Design except that a control group is added


Time Series Design• Involves periodic measurements on the

dependent variable for a group of test units• After multiple measurements, experimental

treatment is administered (or occurs naturally)

• After the treatment, periodic measurements are continued in order to determine the treatment effect

• Diagrammed as:O1 O2 O3 O4 X O5 O6 O7 O8


Statistical Designs• Multiple experiments are conducted

simultaneously to permit extraneous variables to be statistically controlled and

• Effects of multiple independent variables to be measured

• Advantages– Can measure the effects of more than one

independent variable– Can statistically control specific extraneous

variables– Economical designs can be formulated when

each subject is measured more than once.172Dr. R S Mehta, MSND, BPKIHS

Completely Randomized Design• Involves randomly assigning treatments to

group members– Allows control over all extraneous treatments

while manipulating the treatment variable– Simple to administer, but should NOT be used

unless test members are similar, and they are also alike regarding a particular extraneous variable

– Different forms of the independent variable are called “levels.”


Completely Randomized DesignExample

• Grocery store chain trying to motivate consumers to shop in their stores

• 3 possible sales promotional efforts

X1 = offer discount of 5% off total shopping bill

X2 = offer taste sample of selected foodsX3 = control group, no sales promotional

effort applied 174Dr. R S Mehta, MSND, BPKIHS

Completely Randomized DesignExampleSALES PROMOTION TECHNIQUE

LEVELS 5% discount Taste samples No sales promotion

Sales, store 3 Sales, store 5 Sales, store 9

STORES Sales, store 1 Sales, store 8 Sales, store 7

Sales, store 6 Sales, store 4 Sales, store 2

Average sales Average sales Average sales


Randomized Block Design• Randomly assigns treatments to

experimental & control groups• Test units broken into similar blocks (or

groups) according to an extraneous variable– I.e., location, age, gender, income, education,

etc.• Particularly useful when small sample sizes

are necessary


Randomized DesignExample

• Grocery store chain trying to motivate consumers to shop in their stores

• 3 possible sales promotional effortsX1 = offer discount of 5% off total shopping

billX2 = offer taste sample of selected foodsX3 = control group, no sales promotional

effort appliedBlocks = time stores have been in operation177Dr. R S Mehta, MSND, BPKIHS

Latin Square Design• Allows control or elimination of the effect of

two extraneous variables• Systematically blocks in 2 directions by

grouping test units according to 2 extraneous variables

• Includes random assignment of treatments to each cell in the design

• Used for comparing t treatment levels in t rows and t columns– I.e., if we have 3 treatment levels, we must have

3 rows and 3 columns 178Dr. R S Mehta, MSND, BPKIHS

Latin Square Design

Extraneous Variable 2

A B C

Extraneous Variable 1

B C A

C A B

where A, B, & C are all treatments179Dr. R S Mehta, MSND, BPKIHS

Latin Square Design Example

PER CAPITA INCOME

TIME IN OPERATION

High Medium Low

< 5 years X1 X2 X3

5 – 10 years X2 X3 X1

> 10 years X3 X1 X2


Factorial Design• Used to examine the effects that the

manipulation of at least 2 independent variables (simultaneously at different levels) has upon the dependent variable

• The impact that each independent variable has on the dependent variable is referred to as the main effect

• Dependent variable may also be impacted by the interaction of the independent variables. This is called the interaction effect 181Dr. R S Mehta, MSND, BPKIHS

Factorial Design Example• Grocery store chain wants to use 12 of its stores to

examine whether sales would change at 3 different hours of operation and 2 different types of sales promotions

• Dependent variable is change in sales• Independent variables

– Store open 6 am to 6 pm– Store open 6 am to midnight– Store open 24 hours/day– Sales promotion: samples for a free gift– Sales promotion: food samples

• Called a 3 x 2 factorial design• Need 6 experimental groups (3 x 2 = 6)


Factorial Design ExampleHOURS OF OPERATION

SALES PROMOTION

6 am – 6 pm 5 am – midnight 24 hours

Gift stamps

Food samples


Test Marketing• Controlled experiment conducted on a small

segment of the target market• Major objectives

– Determine how well products will be accepted in the marketplace

– Determine how changes in marketing mix will likely affect product success

• Major reason for test marketing is risk reduction– Lose $ 1 million in test market or $ 50 million on product

failure?• Problems

– Expense– Time– Competitors can disrupt 184Dr. R S Mehta, MSND, BPKIHS

Factors to Consider• Population size• Demographic composition• Lifestyle considerations• Competitive situation• Media coverage & efficiency• Media isolation• Self-contained trading area• Overused test markets• Loss of secrecy


Business

Types of Research Designs RS Mehta