As is discussed in this forum and elsewhere, any moving average has a lag. For instance, a simple moving average (SMA) has a lag of half its length so, according to Alexander Elder (Trading for a Living, Section 25. Moving Averages), a SMA would ideally be plotted half its length to the left by setting the Displace input to that amount. And, according to John Ehlers (Signal Analysis Concepts), an exponential moving average (EMA) has a lag of (L - 1) / 2 where L is the Length input for the EMA indicator. That means that a 13 period EMA would ideally be plotted directly under period 7 ( [13 - 1] / 2 = 6 ) ( 13 - 6 = 7 ) rather than under period 13 and a 10 period EMA would ideally be plotter directly under period 5 or 6 ( [10 - 1] / 2 = 4.5 ) ( 10 - 4.5 = 5.5 ) rather than under period 10. But according to Elder, a 10 period EMA should be plotted underneath the 7th or 8th period. So my first question is this - - is Ehlers formula right? And finally - - should we really be displacing EMA indicators in this way? I can imagine doing that and then mentally extrapolating an extension to the present period - but does anyone actually do that or recommend it, especially for intraday trading? So here are the questions restated - - 1. Ehlers and Elder seem to disagree - is Ehlersâ (L - 1) / 2 the correct formula for calculating EMA lag? 2. Is there any value to plotting EMAs displaced to the left by the lag as Elder suggests instead of the traditional way (under the current period bar)?