- Choosing an investigative technique
- Surveys: research in the large
- Case studies: research in the typical
- Experiments: research in the small
- Stating the hypothesis
- Maintaining control over variables
- Making your investigation meaningful
A survey is a retrospective study of a situation to try to document relationships and outcomes. You can record a situation and compare it with similar ones. But you cannot manipulate variables as you do with case studies and experiments.
A case study is a research technique where you identify key factors that may effect the outcome of an activity and then document the activity: its inputs, constraints, resources , and outcome.
By contrast, a formal experiment is a rigorous controlled investigation of an activity, where key factors are identified and manipulated to document their effects on the outcome.
For a retrospective investigation the choice is between a survey or a case study, otherwise between a case study or a formal experiment. High level of control over the variables and replication possibility is a must for experiments.
The goal for your research must be clearly stated; this can be done by stating a hypothesis preferably in quantitative terms. Quantification may lead to the use of surrogate measures. Therefore, you should document the relationship between the measures and the factors they intend to reflect. In particular, you should strive for quantitative terms that are as direct and as unambiguous as possible.
Example. Rather than: "Using the Cleanroom method produces better-quality software than using the SSADM method", state your hypothesis as: "Code produced using the Cleanroom method has a lower number of defects per KLOC than code produced using the SSADM method".