Reactive Arrangements

Reactive arrangements are considered a threat to validity within a research design. Elements within an experimental setting could cause subjects to react differently to the experimental arrangements rather than to the experimental variable alone. Reactive arrangements can be a difficult threat to compensate for, as they may not be decreased or eliminated by random assignment. Yet, if reactive arrangements are present, they may lead to confounded findings and opposing explanations.

In defining threats to validity, Thomas D. Cook and Donald T. Campbell, as well as other researchers, attribute these reactions to the use of measures in a study and/or other reactions to the fact that participants are aware that they are in a study. Reactive arrangements are present when these participant reactions become a functional part of the treatment or independent variable in the study. For example, research participants who receive a pretest might be more or less responsive to the experimental variable as a reactive response. This human reaction impacts the study treatment and may produce reactive results.

Reactive arrangements relate to changes in individuals’ responses that can occur as a direct result of participants being aware of their involvement in a research study. For example, the mere presence of observers in a classroom may cause students to behave differently than if the observer was not present, thereby altering the observation findings. Additionally, reactions to the study procedures may occur and cause reactivity. For example, reactivity may be present if participants respond favorably after receiving a nonactive drug within a study (the placebo effect). Increased motivation to please the researcher may cause a participant to perform higher or lower on a skill or achievement measure to accomplish the expected outcome.

[Page 1380]One way researchers could protect against the threat of reactive arrangements would be for all control treatments to appear authentic without the subjects knowing the outcome measures or expectations. In this situation, it would also be important for the pretest measures to mask the expected outcomes. Oftentimes a no-treatment approach is utilized through a business as usual group, whereas the business as usual treatment would be considered to be weaker or ineffective to the intervention being studied. Assessing outcomes on a delayed basis would also be a less obvious method to protect against the threat of reactive arrangements.

Complete protection against the threat of reactive arrangements may not always be possible, as participants typically make their own hypotheses regarding the purpose and outcomes of a study. Ethically, researchers should provide ample information about the purpose of a proposed study for potential participants to give their informed consent to participate in the study. Reactive arrangements, however, are most often controlled for through carefully planned research designs and selective measurement variables.

See also Ethical Issues in Educational Research; Hawthorne Effect; Placebo Effect