Case study research

Case study research

Marie-Louise Barry

Use of different strategiesStrategy Form of research

questionRequires control of behavioural events?

Focuses on contemporary events?

Experiment How, why? Yes Yes

Survey Who, what, where, how many, how much?

No Yes

Archival analysis Who, what, where, how many, how much?

No Yes/No

History How, why? No No

Case study How, why No Yes

YIN, R.K., 2003. Case Study Research: Design and Methods. . Thousand Oaks, California: SAGE Publications, 3rd edition. Applied Social Research method series. Volume 5.

What is a case study?

• It is a research strategy• Not linked to a particular type of

evidence or method of data collection• Distinguishing characteristic attempts

to examine:– Contemporary phenomenon in real-life

context– Especially when boundaries between

phenomenon context not clearly evidentGeorge, A.L. and Bennett, A., 2005. Case studies and theory development in social sciences. Belfer Center for Science

and International Affairs, Harvard University, Cambridge, Massachusetts.

What is a case study (2)?

• A case study is an empirical enquiry that– Investigates contemporary phenomena in real life

context– Especially when boundary between phenomenon

and context not clear• A case study inquiry further

– Copes with the technically distinctive situation in which there will be many more variables of interest than data points

– Relies on multiple sources of evidence with data needing to converge in a triangulating fashion

– Benefits from prior development of theoretical propositions to guide data collection and analysis


Qualitative vs Quantitative

• Contrast between qualitative and quantitative data does not distinguish the various research strategies

• It is possible to have qualitative surveys or quantitative case studies


Where are case studies used?

• To contribute to knowledge on phenomena of:– Individual– Group– Organisational– Social– Political

• Domains used:– Psychology– Sociology– Political sciences– Social work– Business– Community planning– Economics


Description Explanation Generalisability Realism of

context

Precision of

measurement

Field study:

Primary data

Investigation of behaviour in its

natural setting where the data is

collected by the researchers

↓ ↑↑ ↓

Field study:

Secondary

data

Investigation of behaviour in its

natural setting where the data is

collected by persons or

agencies other than the

researchers.

↓ ↑↑ ↓

Sandura,T.A. and Williams, E.A. 2000. “Research methodology in management: Current practices, trends and implications for future research.” Academy of Management Journal, vol. 43(6), pp. 1248-1264.

External validity

Types of case studies

• Illustrative – descriptive case study that makes the unfamiliar familiar

• Exploratory or pilot – condensed case studies performed before implementing large scale investigation

• Cumulative – Aggregate information from several sites collected at different times

• Critical instance – examine one or more sites for purpose of examining a situation of unique interest

Colorado State University, 2009. Writing guides: Case studies. [online], Available from: http://writing.colostate.edu/guides/research/casestudy/com2b1.cfm Accessed [19 March 2009].

Case study high level methodology

Design case study

Prepare fordata collection

Collect case study evidence

Analyse case study evidence

Report case study

Con

duct

ca

se s

tudy



Design case study

Design case study




Report case study

Con

duct

ca

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tudy

Research design

• Research design is the logic that links the data to be collected (and the conclusions to be drawn) to the initial questions of the study

Data to be collected

Initial question(s)

Research design


Delphi study

Factors

Validity and

Practical application of

Factors

Blueprint

What are the questions?

What are relevant data?

What data to collect?

How to analyse results?

Theory

Validity and

Practical application of

Factors

Blueprint

What are the questions?

What are relevant data?

What data to collect?

How to analyse results?

Definition of research design


Case study

Components of Research designs

• Research question– How and why

• Propositions if any– Propositions are required to keep

the study in feasible limits– Hypothetical story about why acts,

events, structure and thoughts occur

– “Theory of the study”• Units of analysis

– Look at previous studies– Depends on accuracy of research

question• Logic linking data to propositions

and criteria for interpreting findings– Eg pattern matching

What is to be explored?

Purpose of exploration

Criteria by which exploration judged

successful


Types of theories for research design

• Individual theories• Group theories• Organisational theories• Societal theories• Decision making theory• Substantive theory• Make sure that you are testing the correct type

of theoryYIN, R.K., 2003. Case Study Research: Design and Methods. .

Thousand Oaks, California: SAGE Publications, 3rd edition. Applied Social Research method series. Volume 5.

Two types of generalisation

• Statistical generalisation– Inference made about a population– On basis of empirical data collected– About a sample

• Analytic generalisation– Previously developed theory– Used as a template– To compare empirical results of the case study– If two or more cases support the theory – replication can be

claimed– Even more potent if the two or more cases do not support a rival

theoryYIN, R.K., 2003. Case Study Research: Design and Methods. .


Quality of case study research

• Four criteria:– Construct validity – establishing correct operational

measures for concepts being studied– Internal validity – establishing causal relationship

whereby certain conditions are shown to lead to other conditions

– External validity – establishing domain to which a study’s findings can be generalised

– Reliability – demonstrating that operations of a study, such as data collection can be repeated with same results


Quality tests in case studiesTest Case study tactic Phase

Construct validity Multiple sources of evidence

Chain of evidence

Key informant review draft report

Data collection

Data collection

Composition

Internal validity

(NA for exploratory and descriptive case studies)

Analytic tactics:Pattern matching

Explanation building

Address rival explanations

Logic models

Data analysis

Data analysis

Data analysis

Data analysis

External validity Use theory in single-case studies

Use replication logic in multiple-case studies

Research design

Research design

Reliability Use case study protocol

Develop case study database

Data collection

Data collection


To improve validity and reliability

• Prolong data gathering process to ensure accurate findings

• Employ triangulation by using a variety of data

• Conduct member checks by corroborating on interpretation of data with those who provided data

• Collect referential materials (literature survey)• Engage in peer consultation to establish

validity through pooled judgement Colorado State University, 2009. Writing guides: Case studies. [online], Available from:

http://writing.colostate.edu/guides/research/casestudy/com2b1.cfm Accessed [19 March 2009].

Types of case study designs


Single Holistic

Case studydesign

MultipleHolistic

Case study design

Single EmbeddedCase study

design

MultipleEmbeddedCase study

design

HolisticSingle unit of analysis

EmbeddedMultiple units of analysis

Single Multiple

Holistic vs embedded case studies

• Holistic– One unit of analysis– Use where:

• no logical subunits can be identified

• when relevant theory of holistic nature

– Problems:• Global approach avoids

examining specific phenomena in operational detail

• Entire case study at abstract level

• Nature of case study may shift and research question not addressed

• Embedded– More than one unit of

analysis– Subunits add significant

opportunities for extensive analysis

– Important device for focussing a case study

– Problems:• Can focus only at subunit

level• Fails to return larger unit

of analysis


Single vs Multiple case studies

• Single case studies– For specific types of

case study– Rational for single

case study designs cannot be satisfied by multiple cases

• Multiple case studies– Evidence from multiple

case studies often considered more compelling – overall study regarded as more robust

– Requires extensive resources and time

Single holistic case study

• Critical case – when testing well-formulated theory

• Extreme or unique case • Representative or typical

case• Revelatory case –

investigation of phenomenon previously inaccessible to scientific investigation

• Longitudinal case study – studying the same case at different points in time

Case

CONTEXT



Single embedded case study design

• Same types of cases as holistic

• Attention also given to subunit or subunits

• EG– Case – evaluation of a

programme– Embedded units –

projects in the programme

CONTEXT

CaseEmbedded unit

of analysis 1

Embedded unit of analysis n



Replication not sample logic for multiple case studies

• Same as for multiple experiments

• Literal replication – predicts similar results

• Theoretical replication – predicts contrasting results for predictable reasons

• Not the same as sampling logic as for surveys

1. Case studies not the best method for determining prevalence of phenomena

2. Case study covers both phenomena of interest and context – large number of relevant variables which would require an impossibly large number of cases

3. If cases studies had to follow sample logic some important topics could not be empirically investigated



Multiple holistic case study design

• More than one case• Only one unit of

analysisCase

CONTEXT

Case

CONTEXT

Case

CONTEXT

Case

CONTEXT

Case

CONTEXT

Case

CONTEXT

Case

CONTEXT

Case

CONTEXT



Multiple embedded case study design

• Multiple cases• More than one unit of

analysis under study

CONTEXT

CaseEmbedded unit

of analysis 1


CONTEXT

CaseEmbedded unit

of analysis 1


CONTEXT

CaseEmbedded unit

of analysis 1


CONTEXT

CaseEmbedded unit

of analysis 1


CONTEXT

CaseEmbedded unit

of analysis 1


CONTEXT

CaseEmbedded unit

of analysis 1


CONTEXT

CaseEmbedded unit

of analysis 1


CONTEXT

CaseEmbedded unit

of analysis 1




Multiple case study methodDefine and design

Develop theory

Select cases

Design dataCollectionprotocol

ConductCase study 1

Conduct Case study n

Write individualCase study 1

report

Write individualCase study n

report

Prepare, collect and analyse

Draw cross--caseconclusions

Modify theory

Develop policyimplications

Write cross-case Study report

Analyse and concludeYIN, R.K., 2003. Case Study Research: Design and Methods. .



Number of case studies

• Sampling logic criteria regarding sample size not applicable

• Number of literal replications depends on:– Certainty you want about result– Degree of differences in rival theories

• Number of theoretical replications depends on:– Sense of complexity of external validity– The less variation produced in phenomena being

studied by external conditions the fewer case studies required.

Selecting case study designs

• Multiple case study designs preferred over single case study designs:– Analytic benefits to multiple case studies– Possibility of direct replication– Contexts will most probably differ and if a common conclusion can be reach this

means the results are more generalisable

Five misunderstandings of case study research

Flyberg, B, 2006. Five Misunderstandings About Case Study Research. Qualitative Inquiry, 12 (2)

219-245.

Misunderstanding 1 Clarification

General theoretical (context-independent) knowledge is more valuable than concrete, practical (context-dependent) knowledge

Predictive theories and universals cannot be found in the study of human affairs. Concrete, context-dependent knowledge is, therefore, more valuable than the vain search for predictive theories and universals.


One cannot generalise on the basis of an individual case; therefore the case study cannot contribute to scientific development

One can often generalise on the basis of a single case, and the case study may be central to scientific development via generalisation as supplement or alternative to other methods. But formal generalisation is overvalued as a source of scientific development, whereas “the force” of example is underestimated.


The case study is most useful for generating hypotheses; that is, in the fist stage of a total research process, whereas other methods are more suitable for hypothesis testing and theory building

The case study is useful for both generating and testing of hypotheses but is not limited to these research activities alone.


The case study contains a bias towards verification, that is, a tendency to confirm the researcher’s preconceived ideas.

The case study contains no greater bias toward verification of the researcher’s preconceived notions than other methods of inquiry. On the contrary, experience indicates that the case study contains a greater bias toward falsification of preconceived notions than toward verification.


It is often difficult to summarise and develop general propositions and theories on the basis of specific case studies

It is correct that summarising case studies is often difficult especially as concerns case process. It is less correct as regards outcomes. The problems in summarising case studies however, are due more often to the properties of the reality studied than to the case study as a research method. Often it is not desirable to summarise and generalise case studies. Good studies should be read as narratives in their entirety.

Designing case study research

Phase 1:Objectives

DesignStructure Phase 2:

Executestudy according

to designPhase 3:

Analyse findings

George, A.L. and Bennett, A., 2005. Case studies and theory development in social sciences. Belfer Center for Science and International Affairs, Harvard University, Cambridge, Massachusetts.

Phase 1: Research designSpecification of problem

& research objective

Developing a research strategy:Specification of variables

Case selection

Describing the variance in variables

Formulation of data requirements & general questions

George, A.L. and Bennett, A., 2005. Case studies and theory development in social sciences. Belfer Center for Science and International Affairs, Harvard University, Cambridge, Massachusetts.

Specification of problem

and research objective

Develop researchstrategy

Case selection

Describe variance and variables

Formulate data requirements and general questions

Specification of problem

and research objective

Develop researchstrategy

Case selection

Describe variance and variables

Formulate data requirements and general questions

The research problem

• Well informed assessment• Defines the gaps in current state of knowledge• Acknowledges contradictory theory• Notes inadequacies in evidence for existing

theories


Theory building research objectives

• A theoretical/ configurative idiographic case studies. These studies do not directly contribute to theory but provide good descriptions for use in subsequent theory building research.

• Disciplined configurative case studies. These studies use existing theory to explain a case by testing theory.

• Heuristic case studies. These studies are used to identify new variables, hypotheses, causal mechanisms and causal paths.

• Theory testing case studies. These studies are used to test the validity and scope conditions of single or competing theories.

• Plausibility probes. These studies are used to test untested theories and hypotheses to determine whether more in depth testing is warranted.

• Building block studies. These are single case studies or multiple case studies with no variance which can be used as parts of larger contingent generalisations and typological studies.


Prepare for data collection

Design case study




Report case study

Con

duct

ca

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tudy



Prepare for conducting the case study



ResearcherSkills

Conduct pilotScreening

ofcases

Casestudy

protocol

Training for case study

Casestudy

preparation

Researcher skills

• Continued interaction between theoretical issues and data being collected

• Skills required:– Ask good questions– Be a good listener– Be adaptive and flexible– Have firm grasp of issues being studied– Unbiased by preconceived notions



Training for the case study

• If more than one researcher

• Needs to know:– Why the study is being done– What evidence is being sought– What variations can be anticipated and how to

handle variations– What constitutes supportive or contradictory

evidence



Case study protocol

• Major way of increasing case study reliability

• Essential in multiple case studies

• Contains the instrument (questionnaire) as well as the procedure



Sections of a case study protocol

• Overview of case study– Project objectives– Case study issues– Relevant readings on the

topic

• Field procedures– Presentation of credentials– Access to case study sites– General sources of

information– Procedural reminders

• Case study questions– Specific questions– Table shells for arrays of

data– Potential sources of

information for questions

• Guide for the case study report– Outline– Format for data– Use and presentation of

other documentation– Bibliographical information



Screening of cases



Unique case?

Access tospecificcase(s)?

More than30 cases?

Collect quantitative

data

Define criteria

Select 20to 30 cases

Define operational

criteria

Collect preliminary

data

Selectrandom cases

Proceed with case study

YES

YES

NO

NO

YES

NO

Conduct pilot

• Selection of pilot cases:– Convenience, access (personal contact) and

geographical proximity

• Nature of pilot– Broader and less focussed than ultimate plan– Can cover both substantive and methodological

issues

• Reports from pilot cases– Mainly of value to investigators– Explicit about lessons learned from pilot case




Design case study




Report case study

Con

duct

ca

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Six sources of evidence

Physical artefacts

Participant-observation

Direct observation

Interviews

Archivalrecords

Documents

6 sourcesof casestudy

evidence



Documentation

Types Strengths Weaknesses

Letters, memos

Agendas, minutes of meetings

Admin documents

Formal studies or evaluations

Newspaper clippings

Stable – can be reviewed repeatedly

Unobtrusive – not created as result of case study

Exact – contains exact names, references and details

Broad coverage – long span of time, many events, many settings

Retrievability can be low

Biased selectivity if collection not complete

Reporting bias reflects unknown bias of author

Access may be deliberately blocked

Archival records

Types Strengths Weaknesses

Service records

Organisational records

Maps and charts

Lists of names

Survey data

Personal records – diaries, calendars, telephone listings

Stable – can be reviewed repeatedly

Unobtrusive – not created as result of case study

Exact – contains exact names, references and details

Broad coverage – long span of time, many events, many settings

Precise and quantitative

Retrievability can be low

Biased selectivity if collection not complete

Reporting bias reflects unknown bias of author

Access may be deliberately blocked

Accessibility due to privacy



Interviews

• Essential source• Guided conversation -

Open-ended questions• Focussed interview –

follow questions of case study protocol – limited time available

• Formal survey – produces quantitative information

Strengths Weaknesses

Targeted – focussed directly on topic

Insightful – provides perceived causal inferences

Bias due to poorly constructed questions

Response bias

Inaccurate due to poor recall

Reflexivity – interviewee gives what interviewer wants to hear

Recording in interviews

• Matter of personal preference

• Don’t use if:– Interviewee refuses permission– No specific plans for transcribing– Investigator clumsy with recorder – distraction– Investigator thinks recorder is a substitute for

careful listening



Direct observations

• Ranges from formal to casual data collection

• Observational protocols can be developed as part of the case study protocol

• Photographs can be taken to show importance of case characteristics to outside observers


Reality – covers events in real time

Contextual – covers context of event

Time consuming

Selectivity – unless broad coverage

Reflexivity – event may proceed differently as it is observed

Cost – hours needed by human observers



Participant-Observation

• Researcher assumes roles in the case study and participates in events being studied

• Usually applied in anthropological studies


Reality – covers events in real time

Contextual – covers context of event

Insightful into interpersonal behaviour and motives

Time consuming

Selectivity – unless broad coverage

Reflexivity – event may proceed differently as it is observed

Cost – hours needed by human observers

Bias due to investigator’s manipulation of events



Physical artefacts

• Physical or cultural artefacts– Technological device,

tool or instrument, work of art etc

– Used extensively in anthropological research


Insightful into cultural features

Insightful into technical operation

Selectivity

Availability



Principles of data collection

MaintainChain ofevidence

CreateDatabase

MultipleData sources

3 principles



Multiple data sources

Types of

Triangulation(Patton 1987)

Data sourcesData

Triangulation

Among evaluators

InvestigatorTriangulation

Perspectives to same dataset

Theory Triangulation

Of methodsMethodologicalTriangulation



Case study data base

• Data base of raw data that other investigators can review

• Increases reliability of the study

• Must be kept together and accessible

Narratives

Tabularmaterials

Case study documents

CaseStudy notes

Four components



Chain of evidence

Case study report

Case study database

Citations tospecific

sources in database

Case study protocol

Case study Questions




Design case study




Report case study

Con

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It is important to have a general analytic strategy from the start of the case study

The 5 techniques deal with internal validity and external validity

Developingcase

descriptions

Frameworkof rival

explanations

Relying on theoretical propositions

3 strategies

Cross case synthesis

Logic models

Time series analysis

Explanationbuilding

Pattern matching

5 techniques

Analytic manipulations

• Putting information in different arrays• Making matrix of categories and placing

evidence in categories• Creating data displays – flow charts etc• Tabulating frequency of different events• Examining complexity of tabulations and

relationships by calculating second-order numbers such as means and variances

• Putting information in chronological order

Relying on theoretical propositions

• Most preferred strategy– Original objectives and design based on

theoretical propositions– Reflected in research questions– Reflected in review of the literature– Shaped data collection plan


Craft rival explanations

Type of Rival Description or example

Craft rivals

1. The Null Hypothesis The observation is the result of chance circumstances only

2. Threats to validity e.g. history, maturation, instability, testing, instrumentation, regression etc

3. Investigator Bias Experimenter effect, e.g. reactivity in field research

Real-life rival explanations

Type of Rival Description or examples

4. Direct Rival (practice or policy) An intervention (suspect 2) other than the target intervention (suspect 1) accounts for the result

5. Commingled Rival (practice or policy

Other interventions and the target both contributed to the result

6. Implementation rival The implementation process, not the substantive intervention accounts for result

7. Rival theory A theory different from the original theory explains the result better

8. Super rival A force larger than but including the intervention accounts for the result

9. Societal rival Societal trends and not the intervention accounts for the result

Thinking about rival explanations

• Rival explanations must be determined before data collection so that relevant data can be collected.

• The more rivals your analysis addresses and rejects the more confidence you can place in your findings.


Developing a case description

• Should be avoided if at all possible.

• Should only be used if the theoretical propositions or rival explanations strategy will not work.

• Descriptive approach can be used:– To identify an embedded unit of analysis– And develop an overall pattern of complexity


Specific Analytic Techniques

Cross case synthesis

Logic models

Time series analysis

Explanationbuilding

Pattern matching

5 techniques


Pattern Matching

• Most desirable method

• Compares an empirically based pattern with a predicted one or with several alternative predictions

• If patterns coincide the results help to strengthen internal validity

• Rival explanations can also be used for pattern matching YIN, R.K., 2003. Case Study Research: Design and Methods. .


Explanation Building

• Special type of pattern matching

• The goal is to analyse case study data by building explanation about the case

Initial theoretical statement

Compare toInitial case

Revise statement

Compare Case to revision

Compare to 2nd

3rd or morecases

Repeat process


Time Series Analysis• Case study objective to examine relevant how and why questions about the

relationship of events in time – not merely to observe time trends


Logic Models

• The logic model stipulates a complex chain of events over time

• Events are staged in a repeated cause-effect-cause-effect pattern

• Complexity arises in that multiple stages may exist over an extended period of time

• Four types of logic models (dependant on unit of analysis):– Individual level logic model– Firm or organisational level

logic model– An alternative configuration

for an organisational level logic model

– Program-level logic model


Cross Case Synthesis

• For a moderate number of case studies:– Create word tables that display data for

individual cases according to a uniform framework


High quality analysis

• Analysis must attend to all the evidence

• Analysis should address all rival explanations

• Analysis should address the most significant aspects of the case study

• Use own prior expert knowledge


Report case study

Design case study




Report case study

Con

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Six compositional structures

Type of structure

Explanatory Descriptive Exploratory

Linear analysis X X X

Comparative X X X

Chronological X X X

Theory building

X X

Suspense X

Unsequenced X


What makes an exemplary case study? (1)

• Case study must be significant– Individual case(s) are unusual and of general interest– Underlying issues important in theoretical or practical

terms– Both preceding conditions met

• Case study must be complete– Boundaries must be clearly set and tested– Demonstrate that exhaustive effort has been taken to

collect all the evidence– Lack of time and resources must not be the reason

why the case study ended – the study must be designed to take these into account from the outset.

What makes an exemplary case study? (2)

• Case study must consider alternative perspectives– For explanatory case studies consider and analyse rival

propositions– Seek those alternatives that seriously challenge the case study

design

• Case study must display sufficient evidence– Relevant evidence must be presented judiciously and effectively

so that the reader can reach independent judgement.

• Case study must be composed in an engaging manner– Clarity of writing increases with rewriting

Case study research

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