11% OF A LECTURE is all that first year college students typically capture in their notes, according to research. Even the best college level note-takers capture less than 75% of the critical ideas presented (Kiewra,1985.)     

   

Studies also show that during a 20 minute lecture, students retain approximately 70% of what is presented in the first ten minutes, but only 20% of what is presented in the last ten minutes, and less thereafter. The bottom line is, students need help retaining what is presented to them. The best way to do this is with instructor-provided notes.
The quality of notes taken during a lecture have a direct relationship to retention of the material presented. There are many theories on how to deal with this problem, from teaching students how to take better notes, to shortening lectures down to 20 minutes. 

Both of these examples have been proven to provide better results but may not be an option for many instructors. Teaching students better note taking skills is a course in itself and many instructors do not dare take this task on. Shortening the lecture is not an option at all for most instructors today because of the large amount of material they are asked to present.
The best solution seems to be instructor-provided notes prior to the lecture, followed by full notes after the lecture for the student to review before being assessed. Partial notes can be in the form of outlines, matrices, or skeletal notes.

Of these, the skeletal format has gained the widest support (Hartley,1978; Russell et al., 1983; Kiewra,1985). In this format, the main ideas of the lecture are provided, usually including the hierarchical relationships among them (e.g., by arranging them in outline or schematic form), with spaces left for students to fill in pertinent information, such as definitions, elaborations, or other explicative material, as they listen to the lecture. There is a positive correlation between the amount of white space in your skeletal outline and the amount of notes your students will take. (Hartley & Davies)

The same studies show that student retention increases when the student takes notes during class, but providing the main points ensures that they do not miss key concepts and helps them keep the content organized.

Providing students with the full notes of the lecture for review prior to being assessed allows them to fill in any critical parts they may have missed. Kiewra (1985) reported that students who only review detailed notes provided by the instructor after the lecture generally do better on subsequent fact-based tests of the lecture than do students who only review their own notes. In fact, students who did not even attend the lecture but reviewed the instructor’s notes scored higher on such tests than did students who attended the lecture and took and reviewed their own notes. Unlike the students’ notes, the instructor’s notes contain all the critical ideas of the lecture.
So why not provide students with the full lecture notes all the time? In some cases, providing students with full notes even afterward can have some negative effects. The availability of full notes may encourage absenteeism among students who fail to recognize the additional benefits of attending lectures.
This argument, together with the fact that many instructors object to preparing and providing full notes, makes this option somewhat problematic. Nevertheless, if you want your students to retain as much of your lessons as possible, this is a well-supported way to do it.
Here are the strategies in order of effectiveness: 
       1.Skeletal notes before, with instructor-provided notes after
       2.Instructor-provided notes only
       3.Skip lecture and review instructor-provided notes
       4.Review own notes

Preston Gales
Gales, P. (2005). Instructor-provided notes. In B. Hoffman (Ed.), Encyclopedia of Educational Technology.