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Fidelity & Adaptation

Fidelity & Adaptation

Choosing the right prevention program or strategy is so important. Once chosen, it is critical that a program/strategy is implemented with fidelity to get the best possible outcomes. Fidelity refers to the degree that an implemented program/policy stays true to what its developers intended. Let's examine further on the factors to be considered 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 dosage 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 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.

When choosing an evidence-based program (EBP), it is important to consider how a program will fit with the cultural values of your target population, as well as how it will fit with the setting and resources available for implementation. If a program does not make cultural sense to your target audience, then it is unlikely to be effective. For this reason, a program developed and empirically supported in one community simply may not work in another. Additionally, a program needs to be feasible and practical in your specific setting to be implemented effectively.

However, it is possible that no one EBP is a perfect match for your situation. When this happens, it is often necessary to modify an existing program to better fit your needs.

  • Adaptation refers to any change a prevention program undergoes to meet specific needs. Adaptation can include two types of changes to programs:
  • Content: Making changes or additions to program manuals, tasks, and tools so that the content is more relevant to the target population. In order to be effective, these changes should reflect the use of both culturally-relevant names, terms, and examples (surface structure) and culturally-relevant concepts, themes, and issues (deep structure).
  • Delivery: Making changes to the way programs are carried out (e.g., methods, online, or in the classroom)

Most programs are characterized by a set of "key ingredients" which are thought to be the main catalysts of program effectiveness. The rest of the program surrounds and supports these key ingredients. When making modifications to a program, it is important to identify and keep the "key ingredients" in order to maintain program effectiveness. However, often other facets of the program can be changed without significantly diminishing program effectiveness. Consult with the program developer to discuss adaptations that you plan to make and their potential impacts to the program's effectiveness. When changes are made to a program, it is critical that they are recorded and monitored so that you can later understand if they had some major effect on the intended outcomes. Well-designed adaptations can actually increase the effectiveness of your program.


  • 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.
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  • SAMHSA. (2019, June 20). A Guide to SAMSHA’s Strategic Prevention Framework. Retrieved from
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  • SAMHSA. (2019, June 20). A Guide to SAMSHA’s Strategic Prevention Framework. Retrieved from