Each year in the U.S., billions of dollars are spent by companies and individuals on leadership development programs. A critical question is: does leadership development work? The answer is, "yes," but some programs seem to work better than others.

A series of meta-analyses, which are essentially statistical studies of studies, shows that across all efforts to develop leadership there are modest, positive improvements in leadership. The first, by psychologist Bruce Avolio and his colleagues looked at 100 years of leadership development programs. This meta-analysis showed that across programs, regardless of the type of training, leadership development worked.

More recent analyses show that certain types of leadership development, based on theories such as transformational leadership, and Pygmalion leadership training (teaching leaders to hold positive expectations for followers' performance, and to convey those positive expectations) work best.