Measurement Reactivity in a Randomized Clinical Trial Using Self-Reported Data.

PURPOSE: The objective of this article is to describe how self-monitoring contributed to measurement reactivity in a randomized clinical trial (RCT). The implications of measurement reactivity on self-monitoring and suggestions for minimizing its effect will be discussed.

DESIGN

The study involved a secondary data analysis of responses from 145 participants who completed a 12-month long RCT. The original sample consisted of 202 community-living adults with long-term indwelling urinary catheters.

METHODS

The data analyzed were from the participants' brief responses to the final study question concerning their perceived study participation value. The data were discussed and coded iteratively until three researchers reached consensus. At the end, each item was recoded into eight categories and minor codes.

FINDINGS: Our belief that the calendar was the probable cause of reactivity was not fully supported as the control group also learned about paying attention to urinary catheter problems by the questions asked through the seven bimonthly interviews.

CONCLUSIONS

The calendar and interview questions were reactive by increasing participants' self-monitoring of catheter problems. Specifically, the frequent interviews exposed participants to catheter-related concerns and provided them with ideas as to how to better manage them.

CLINICAL RELEVANCE: This article provides insight related to the internal validity threat of measurement reactivity in RCTs and gives suggestions to reduce its effects.