All 25 videos retain this basic format. There is an introduction, followed by an explanation of important terms that are going to be heard. The subject matter is split into three parts, with relevant academic research after each part. Engaging, but not overwhelming, illustrations help retain attention. At the end there is a short review.
The videos are kept to a length of about 20 minutes, because it's been shown that's about how long people can pay attention (ie TED talks).
My framework for the video design was based on Richard Mayer's multimedia principles of learning.