Conference Countdown
San Diego, Calif.
October 30 - November 1, 2015
  • membership
  • my account
  • help

    We are here to help!

    1703 North Beauregard Street
    Alexandria, VA 22311-1714
    Tel: 1-800-933-ASCD (2723)
    Fax: 703-575-5400

    8:00 a.m. to 6:00 p.m. Eastern time, Monday through Friday

    Local to the D.C. area, 703-578-9600, press 2

    Toll-free from U.S. and Canada, 1-800-933-ASCD (2723), press 2

    All other countries (International Access Code) + 1-703-578-9600, press 2

  • Log In
  • Forgot Password?


Conference on Educational Leadership

Conference on Educational Leadership

Connect with the top leaders, develop your leadership skills, and leave empowered with new ideas to put into practice in your school or district

Learn more and register.



ASCD respects intellectual property rights and adheres to the laws governing them. Learn more about our permissions policy and submit your request online.

Policies and Requests

Translations Rights

Books in Translation

Premium Member Book (Aug 2004)

Log in to read this chapter.


Building Background Knowledge for Academic Achievement

by Robert J. Marzano

Table of Contents

Technical Notes

This section contains technical notes referred to in the text.

Technical Note 1

To compute the average correlation between background knowledge and academic achievement, I first analyzed the correlations from the studies reported in Chapter 1 to determine outliers, using techniques reported by Tukey (1977). An outlier is a correlation that does not “fit” within a given set. It is either much larger or much smaller than the other correlations. I then transformed the remaining correlations using the Fisher Z transformation and computed the average of these transformed correlations. This step is necessary because differences between correlations do not constitute an equal interval scale. That is, differences between large correlations are not mathematically equal to differences between small correlations. The average Z transformed correlation was then transformed back to the original metric.

Technical Note 2


You must be an ASCD Premium member to view this content.

Log in.


Log in to submit a comment.

To post a comment, please log in above. (You must be an ASCD EDge community member.) Free registration