Increasing the frequency or duration (e.g. number of weekly sessions) of an evidence-based intervention may not increase the beneficial effects, and may lead to negative effects.
For example, just because a particular teaching method (e.g. collaborative learning) has been shown to be beneficial does not mean that using only this teaching method will lead to even better results.
BEWARE of claims that suggest that more of the same intervention will increase its benefits.
REMEMBER: If an intervention is believed to be beneficial, do not assume that more of it is always better.