Whatever the issue and your approach to addressing it, the program may result in some outcomes that were not intended.
These outcomes may be positive or negative.
A negative outcome could be that while an intervention targeting high-risk behavior might reduce the intended behavior, it might result in an increase in another high-risk behavior.
On the other hand, a program or intervention could also have positive unintended outcomes. For example, the reduction in a targeted high-risk behavior might also encourage a simultaneous reduction in another high-risk behavior.
Unintended outcomes can have an impact on how outcomes are interpreted and can even compromise the whole program. Therefore, if you can anticipate some of these, particularly the negative ones, you can attempt to mitigate their possible impact on the validity of your results and their interpretation.
Some other unintended consequences to consider include stigmatization of program participants or misinterpretation of intended program messages. A program may also have differential and unwanted effects on different sub-groups of participants. For example, men and women or participants across various socio-economic groups may relate to the program approach or content differently, and show divergent trends in measured outcomes.