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Identifying needs andestablishing

requirements



Overview T he importance of requirements

D ifferent types of requirements

D ata gatheringT ask descriptions: Scenarios

Use Cases

Essential use cases

T ask analysis: H TA



What, ho w and w hy? W hatTw o aims:1. Understand as much as possible aboutusers, task, context2. Produce a stable set of requirements

Ho w :D ata gathering activitiesD ata analysis activitiesExpression as µrequirements¶ A ll of this is iterative





Establ

i sh

i ng

requirement

s

W hat do users w ant? W hat do users µneed¶?Requirements need clarification, refinement,completion, re-scoping

Input: requirements document (maybe)Output: stable requirements

W hy µestablish¶?

Requirements arise from understanding users¶ needsRequirements can be justified & related to data



D iffere nt k i nd s o f requireme nt s F unctional:

² W hat the system should do²Historically the main focus of

requirements activities(Non-functional: memory size, response

time... ) D ata:

² W hat kinds of data need to be stored?²Ho w w ill they be stored (e.g.database)?



D iffere nt k i nd s o f requireme nt sEnvironment or context of use:

²physical: dusty? noisy? vibration? light?heat? humidity? «. (e.g. OMS insects, AT M)

²social: sharing of files, of displays, in paper,across great distances, w ork individually,privacy for clients²organisational: hierarchy, I T department¶sattitude and remit, user support,communications structure and infrastructure,availability of training² Technical: w hat tech? compatible w ith?



D iffere nt k i nd s o f requireme nt s

Users: W ho are they?²Characteristics: ability, background,attitude to computers

²System use: novice, expert, casual, frequent²Novice: step-by-step (prompted), constrained,clear information²Expert: flexibility, access/po w er² F requent: short cuts²Casual/infrequent: clear instructions, e.g.menu paths



D iffere nt k i nd s o f requireme nt s

Usability:learnability, throughput, flexibility,attitude

Note that user requirements and usabilityrequirements refer to different things



A n extreme example: KordGrip



K i nd s o f requireme nt s

W hat factors (functional, data, environmental,user, usability) w ould affect the follo w ingsystems?

Self-service filling and payment system for apetrol (gas) station

A system for use in a univeristy¶s self-servicecafetaria that allo w s users to pay their foodusing a credit system



D ata gath eri ng t ec hn ique s (1)Questionnaires:

² A series of questions designed to elicitspecific information

² Questions may require different kinds of ans w ers:simple YES/NO; choice of pre-suppliedans w ers; comment

²Often used in conjunction w ith othertechniques

²Can give quantitative or qualitative data²Good for ans w ering specific questions from

a large, dispersed group of people



D ata gath eri ng t ec hn ique s (2)Intervie w s:

² F orum for talking to people

²Structured, unstructured or semi-structured

²Props, e.g. sample scenarios of use,prototypes, can be used in intervie w s

²Good for exploring issues

²But are time consuming and may beinfeasible to visit everyone



D ata gath eri ng t ec hn ique s (3)W orkshops or focus groups:

²Group intervie w s²Good at gaining a consensus vie w and/or

highlighting areas of conflict



D ata gath eri ng t ec hn ique s (4)Naturalistic observation:

²Spend time w ith stakeholders in theirday-to-day tasks, observing w ork as ithappens

²Gain insights into stakeholders¶ tasks²Good for understanding the nature and

context of the tasks²But, it requires time and commitment

from a member of the design team, andit can result in a huge amount of data²Ethnography is one form



D ata gath eri ng t ec hn ique s (5)Studying documentation:

²Procedures and rules are often w rittendo w n in manuals

²Good source of data about the stepsinvolved in an activity, and anyregulations governing a task

²Not to be used in isolation²Good for understanding legislation, and

getting background information²No stakeholder time, w hich is a limiting

factor on the other techniques



C hoo s i ng b e t wee n t ec hn ique s

D ata gathering techniques differ in t w o w ays:1. A mount of time, level of detail and risk associatedw ith the findings

2. Kno w ledge the analyst requires

T he choice of technique is also affected by the kind of task to be studied:

²Sequential steps or overlapping series of subtasks?²High or lo w , complex or simple information?² Task for a layman or a skilled practitioner?





P r obl em s wi th data gath eri ng (1)Identifying and involving stakeholders:users, managers, developers, customer reps?,

union reps?, shareholders?Involving stakeholders: w orkshops, intervie w s,w orkplace studies, co-opt stakeholders onto thedevelopment team

µReal¶ users, not managers:

traditionally a problem in soft w are engineering,but better no w



P r obl em s wi th data gath eri ng (2)

Requirements management: version control,o w nershipCommunication bet w een parties:

² w ithin development team² w ith customer/user²bet w een users« different parts of an

organisation use different terminology D omain kno w ledge distributed and implicit:

²difficult to dig up and understand²kno w ledge articulation: ho w do you w alk?

A vailability of key people



P r obl em

s wi th data gath eri ng (3)

Political problems w ithin the organisation

D ominance of certain stakeholders

Economic and business environment changes

Balancing functional and usability demands



S o me ba s ic g ui d e l i n e s

F ocus on identifying the stakeholders¶ needs

Involve all the stakeholder groups

Involve more than one representative fromeach stakeholder group

Use a combination of data gathering

techniques



S o me ba s ic g ui d e l i n e s

Support the process w ith props such as prototypes

and task descriptionsRun a pilot session

You w ill need to compromise on the data you collectand the analysis to be done, but before you canmake sensible compromises, you need to kno w w hatyou¶d re ally like

Consider carefully ho w to record the data



W hat kinds of data gatheringtechniques?

Consider w hat kinds of data gathering w ould be appropriate andho w you might use the different techniques introducedabove. You should assume that you are at the beginning of the development and that you have sufficient time andresources to use any of the techniques.

You are developing a ne w soft w are system to support a smallaccountant's office. T here is a system running already w ithw hich the users are reasonably happy, but it is looking datedand needs upgrading.

You are developing a w ebsite for a young person's fashion e-commerce site.



Data

i nt

erpretat

i on and analy

s i s

Start soon after data gathering session

Initial interpretation before deeper analysis

D ifferent approaches emphasize differentelements e.g. class diagrams for object-oriented systems, entity-relationship diagrams

for data intensive systems



T a s k d e s crip t i on s

Scenariosan informal narrative story, simple, µnatural¶,personal, not generalisable

Use cases²assume interaction w ith a system²assume detailed understanding of the interaction

Essential use cases²abstract a w ay from the details²does not have the same assumptions as use cases



S ce na ri o f o r a library catalog service

³Say I want to find a book by George Jeffries. I don't remember the titlebut I know it was published before 1995. I go to the catalog and enter my user password. I don't understand why I have to do this, since I can't get into the library to use the catalog without passing throughsecurity gates. However, once my password has been confirmed,I am given a choice of searching by author or by date, but not thecombination of author and date. I tend to choose the author optionbecause the date search usually identifies too many entries. After about 30 seconds the catalog returns saying that there are no entriesfor George Jeffries and showing me the list of entries closest to the oneI've sought. When I see the list, I realize that in fact I got the author'sfirst name wrong and it's Gregory, not George. I choose the entry I want and the system displays the location to tell me where tofind the book.´



U s e c a s e f o r a library catalog service

The use case for "Locate book" might be something like this:

1. The system prompts for user name and password.2. The user enters his or her user name and password into the catalog system.3. The system verifies the user's password.4. The system displays a menu of choices.5. The user chooses the search option.6. The system displays the search menu.7. The user chooses to search by author.8. The system displays the search author screen.9. The user enters the author's name.10. The system displays search results.11. The user chooses the required book.12. The system displays details of chosen book.13. The user notes location.14. The user quits catalog system.



A lt er nat ive c o ur s e s f o r a library

catalog serviceSome alternative courses:4. If user password is not valid

4.1 The system displays error message.4.2 The system returns to step 1.

5. If user knows the book details5.1 The user chooses to enter book details.5.2 The system displays book details screen.5.3 The user enters book details.5 .4 The system goes to step 12.

One other main actor: ³Librarian´, A use casefor the Librarian w ould be ³Update Catalog´



Ex a mp l e u s e c a s e d i ag r a m f o r a library catalogservice

L i r r r

L i r ri

l c t k

U t c t l



Ex a mp l e e ss e nt i al u s e c a s e f o r a library catalogservice

locateBookUSER IN T ENT ION SYS T EM RESPONSIBILI T Yidentify self

verify identityrequest appropriate details

Offer kno w n detailsoffer search result

note search resultsQuit system

close



T a s k analy s i s

T ask descriptions are often used to envision ne w systems or devices

T ask analysis is used mainly to investigate anexisting situationIt is important not to focus on superficial activities

W hat are people trying to achieve?W hy are they trying to achieve it?Ho w are they going about it?

Many techniques, the most popular is HierarchicalT ask A nalysis (H TA )



H ier a rc h ic al T a s k A naly s i s

Involves breaking a task do w n into subtasks, thensub-sub-tasks and so on. T hese are grouped asplans w hich specify ho w the tasks might beperformed in practice

HTA focuses on physical and observable actions,and includes looking at actions not related tosoft w are or an interaction device

Start w ith a user goal w hich is examined and themain tasks for achieving it are identified

T asks are sub-divided into sub-tasks



Ex a mp l e H ier a rc h ic al T a s k A naly s i s0 . In order to borro w a book from the library

1. go to the library2. find the required book

2.1 access library catalogue

2.2 access the search screen2.3 enter search criteria2.4 identify required book2.5 note location

3. go to correct shelf and retrieve book

4. take book to checkout counterplan 0: do 1-3-4. If book isn¶t on the shelf expected, do 2-3-4.plan 2: do 2.1-2.4-2.5. If book not identified do 2.2-2.3-2.4.



Ex a mp l e H ier a rc h ic al T a s k A naly s i s

(g r a ph ic al)B orrow abook from thelibrary

go to thelibrary

find requiredbook

retrieve bookfrom shelf

take book tocounter

321 4

0

accesscatalog

accesssearchscreen

enter searchcriteria

identifyrequiredbook

notelocation

plan 0:do 1-3-4.If book isn¶t on the shelf expected, do 2-3-4.

plan 2:do 2.1-2.4-2.5.If book not identified from information available, do 2.2-2.3-2.4-2.5

2.1 2.2 2.3 2.4 2.5



S umm a r y Getting requirements right is crucial

T here are different kinds of requirement, each issignificant for interaction design

T he most commonly-used techniques for datagathering are: questionnaires, intervie w s, focusgroups and w orkshops, naturalistic observation,studying documentation

Scenarios, use cases and essential use cases

can be used to articulate existing andenvisioned w ork practices. T ask analysis techniques such as H TA help to

investigate existing systems and practices



A ssignment: identifying needs andestablishing requirements

T ugas besar adalah mendesain dan mengevaluasisebuah w ebsite interaktif untuk melakukanbooking tiket secara online (tiket konser, bioskop,teater )

T ugas:a) Mengidentifikasikan kebutuhan user (users¶ needs) utk

w ebsite ybs. A da beberapa cara yang bisa dilakukan:Misal: melakukan observasi pada orang-orang yangmenggunakan jasa agen tiket, belajar dari pengelamansendiri pada saat membeli tiekt, melihat w ebsite bookingtiket yang sejenis, diskusi dengan teman atau keluargamengenai pengelaman mereka, dll. Catat (simpan) dataA nda.



A ssignment: identifying needs andestablishing requirements

b) Berdasarkan user requirement A nda,pilih dua profil user dan hasilkan satuskenario besar untuk setiap profil user.D eskripsikan bagaimana seharusnyauser berinteraksi dengan sistem.

c) D engan menggunakan skenario diatas,buatlah suatu task analysis dengantugas utama (main task) berhubungandengan sistem booking tiket, misal:booking sebuah tiket

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