Ease of Movement is a momentum indicator created by Richard W. Arms, Jr. that compares the price change of a security to its volume. It's useful in assessing the strength of a trend.
It is calculated as follows:
Distance Moved = ((H + L)/2 - (Prior H + Prior L)/2)
Box Ratio = ((V/100,000,000)/(H - L))
1-Period EMV = ((H + L)/2 - (Prior H + Prior L)/2) / ((V/100,000,000)/(H - L))
14-Period Ease of Movement = 14-Period simple moving average of 1-period EMV
Read more about EOM in this AAII Journal article.