I was asked to determine why the clickthrough rate on an eNewsletter was decreasing in recent months. As with many such questions, BJ Fogg’s Behavior Model is a great place to start:
Behavior = Motivation + Ability + Trigger
Some behaviors are more difficult to perform; or, in the case of product design, elicit from users. Regardless of the difficulty, their must be adequate motivation for the user to perform the task, the user must have the physical/mental/emotional ability to perform the task, and there must be a trigger to prompt the execution of the task. Additionally, all three of these must occur at the same time in order for the behavior to occur.
If the combined weight of these three factors does not meet the difficulty threshold for the task (at the time the the task needs to be performed), then the behavior will not occur. For example, imagine you want to wake up an hour earlier than usual in order to exercise: