Steps for Calculating and Reporting on Reach
The following is a recommended sequence of standard steps for calculating and reporting on Reach:
- Enumerate all potential participants in the target population (usually defined geographically).
- List the reasons for and number of exclusions by the investigators or program.
- List the number of “lost or indeterminate cases” – e.g., wrong information, not able to be contacted, moved, no answer.
- List the number of known eligible participants who were offered participation.
- Divide the number of participants (persons beginning or coming to the first session of a program) by #4 to determine Percent Participation.
- (Optional) A sensitivity analysis can be conservatively calculated by adding #3 and 4 in the denominator and then dividing, as in #5.
- Determine the representativeness of participants by comparing demographic characteristics and other relevant variables between participants and nonparticipants.
- Report the most common reasons for declining participation.