A cumulative case study is a research approach that aggregates data collected from several distinct sites at different points in time.
Understanding Cumulative Case Studies
In research and evaluation design, a cumulative case study stands out from single or multiple site case studies conducted concurrently. Its defining characteristic is the aggregation—or bringing together—of information gathered across multiple locations and potentially over a staggered timeframe.
According to the provided reference: "Cumulative case studies aggregate data from several sites collected at different times."
This means that instead of analyzing a single event or context in depth (like a typical case study), or looking at multiple contexts simultaneously, a cumulative study builds a broader picture by combining findings from cases studied independently at various points.
Key Characteristics
- Aggregation of Data: The core process involves compiling and synthesizing data from different individual case studies.
- Multiple Sites: Data comes from more than one location, program, or unit of analysis.
- Different Times: The data collection at each site or for each individual case may occur sequentially rather than all at once.
Why Use a Cumulative Approach?
Evaluators often choose a cumulative case study when they need to:
- Build a stronger base of evidence over time or across different contexts.
- Identify patterns, trends, or variations that emerge when comparing cases studied separately.
- Study the evolution or impact of a phenomenon as it unfolds or is implemented in different settings or stages.
- Utilize existing case study data to inform new insights or build a larger, more comprehensive picture.
For example, a cumulative case study might involve analyzing evaluations of a training program delivered to different cohorts of employees in various branch offices over several years. By aggregating the data, researchers can look for common successes, persistent challenges, or variations related to site-specific factors or changes made to the program over time.
When considering case study as an evaluation design, evaluators must carefully determine the research question and select the type of case study (like a cumulative one) that is best suited to answer it effectively, especially when comparing data collected at different times and places.
