This is not recommended. Reducing the total number of classes, for example, by skipping some of the lessons or teaching fewer but slightly longer lessons, is considered a red-light adaptation.
Research studies of curricula demonstrate that deleting activities or classes can reduce their effectiveness. As demonstrated by the logic model for each program, every activity is designed to affect an important risk or protective factor that, in turn, affects sexual risk behavior. Omitting one or more of the classes dilutes the program’s ability to address one or more of these factors, and, therefore, can reduce its overall effectiveness.
If lessons are shortened, then there will be cuts to activities, or less time for discussion, reflection, personalization, review, etc. Any of these changes can reduce effectiveness.
Lengthening individual classes can allow more time for review of previous lessons, discussion, questions, roleplay practice, personalization activities and other activities, which may even increase effectiveness. However, teaching two or more lessons in one block period can cause learners to become less attentive and gives them less time for reflection between classes. Also, while some curriculum lessons may combine together well to fit block periods, some do not. Including too much content in one class period may also reduce learner attentiveness and retention.