Implementation Fidelity


Implementation Fidelity

Choosing the right prevention program is so important. Once chosen, it is critical that a program is implemented with fidelity to get the best possible outcomes. Fidelity refers to the degree that an implemented program stays ‘true’ to what its designers intended. Consider the following factors when attempting to faithfully replicate a prevention program. 

  • Adherence: How much did your program stick to the original design? It is not always possible or even desirable (in the case of cultural adaptations) to administer a program exactly as designed. However, it is important to note any deviations from the design to see if these have impacted your outcomes in some way.
  • Dose: How much of the program did your target population receive? This refers to the number of classes or meetings participants actually attended, as well as the length and intensity of the program activities. It is important to keep track of the dose because it is quite possible that participants who attended more activities will show more change than those who left the program early.
  • Quality of delivery: In the end, how high was the quality of your program delivery? This refers to the level of staffing and training as well as the resources deployed during program activities. It is possible to follow a program manual precisely but without a focus on the quality of the delivery. This is often the result of poor planning, inadequate training, or lack of enthusiasm on the part of program staff.
  • Participant responsiveness: How did your target population respond to the program? A successful prevention program is not only well-implemented with a high level of quality, but it is also relevant to your participants. If your program is not meaningful and useful to your target audience, then even high-quality implementation will result in disappointing outcomes. Therefore, measuring the level of participant engagement is critical to understanding whether a program is effective.

However, it is also important to remember that often programs need to be modified to better fit the target population and the setting in which they are implemented. These modifications are called adaptations. Adaptations can be very useful and can even be a critical component of program success, but they can also compromise the fidelity with which a program is implemented. It is, therefore, necessary to find the right balance between adaptation and implementation fidelity.



Castro, F., Barrera, M., and Martinez, C. (2004). The cultural adaptation of prevention interventions: resolving tension between fidelity and fit. Prevention Science, 5(1), 41-45.
Dusenbury, L., Brannigan, R., Falco, M., and Hansen, W. (2003). A review of research on fidelity of implementation: implications for drug abuse prevention in school settings. Health Education Research Theory & Practice, 18(2), 237-256. 
Moncher, F., and Prinz, R. (1991). Treatment fidelity in outcome studies. Clinical Psychology Review, 11, 247-266.
SAMHSA. (2015, October 1). Step 4: Implement. Retrieved from