Case study research Marie-Louise Barry
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 evident
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
To contribute to knowledge on phenomena of: Individual Group Organisational Social Political Domains used: Psychology Sociology Political sciences Social work Business Community planning Economics Where are case studies used?
External validity 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.
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
Design case study Prepare for data collection Conduct case study Collect case study evidence Analyse case study evidence Report case study Case study high level methodology
Design case study Design case study Prepare for data collection Conduct case study Collect case study evidence Analyse case study evidence Report case study
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 Research design Initial question(s) Data to be collected
Validity and Validity and Delphi study Theory Practical application of Practical application of Factors Factors Factors Blueprint Blueprint What are the questions? What are the questions? What are relevant data? What are relevant data? What data to collect? What data to collect? How to analyse results? 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 theory
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 theory
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
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
Single Multiple Single Holistic Case study design Multiple Holistic Case study design Holistic Single unit of analysis Single Embedded Case study design Multiple Embedded Case study design Embedded Multiple units of analysis Types of case study designs
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 Holistic vs embedded 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 vs Multiple case studies
CONTEXT Case 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
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 Case Embedded unit of analysis 1 Embedded unit of analysis n Single embedded case study design
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 Case studies not the best method for determining prevalence of phenomena Case study covers both phenomena of interest and context – large number of relevant variables which would require an impossibly large number of cases If cases studies had to follow sample logic some important topics could not be empirically investigated Replication not sample logic for multiple case studies
More than one case Only one unit of analysis Multiple holistic case study design
Multiple cases More than one unit of analysis under study Multiple embedded case study design
Define and design Select cases Develop theory Design data Collection protocol Draw cross--case conclusions Prepare, collect and analyse Modify theory Conduct Case study 1 Write individual Case study 1 report Develop policy implications Write individual Case study n report Conduct Case study n Write cross-case Study report Analyse and conclude Multiple case study method
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.
Designing case study research Phase 1: Objectives Design Structure Phase 2: Execute study according to design Phase 3: Analyse findings
Phase 1: Research design Specification of problem & research objective Developing a research strategy: Specification of variables Case selection Describing the variance in variables Formulation of data requirements & 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 Prepare for data collection Conduct case study Collect case study evidence Analyse case study evidence Report case study
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
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 Sections of a case study protocol
Unique case? YES Define criteria Collect preliminary data NO Access to specific case(s)? YES Collect quantitative data Define operational criteria NO More than 30 cases? Select 20 to 30 cases YES Select random cases NO Proceed with case study Screening of cases
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
Collect case study evidence Design case study Prepare for data collection Conduct case study Collect case study evidence Analyse case study evidence Report case study