How much reading is appropriate to give to students? I'm designing an introductory undergraduate course on social science which is mostly based on not-so technical textbooks and articles (little math involved). Essays will be the key form of evaluation. I want to have an idea of how much readings to give to my students per week. The credit system my university uses is such that for 1 hour of contact teaching 1 hour of autonomous work is expected. I have 2 hours of contact teaching per week. If I assume students can read, say 20 pages per week (assume average article/journal size), I can give them 40 pages per week as background reading. This, I assume does not include their own study of textbooks (otherwise it would be impossible to give them readings!).

Do you have an idea of what sort of relation is used in terms of contact hours versus pages of reading?
It really depends on the focus of the class, and what other homework you are giving students.

Certain classes are expected to have more reading.  Societal and philosophical theory fields are heavy on reading, as are (obviously) literature classes. 

Remember, different students will read at different rates, and the more you cover the less detail you can cover.  It's sometimes better to go into deeper depth than to cover more for both these reasons.

It is important you disclose the reading to students as early as possible, preferably before they apply for your class.  At the very least all major reading assignments longer than a few pages should be disclosed on the first day of class.  This gives students that need to time to read ahead.