I hope you like this representation of the Mansfield Relative Strength Indicator.
The calculations have been made based on the following formulas:
Standard Relative Performance indicator
RP = ( stock_close / index_close ) * 100
Mansfield Relative Performance indicator
MRP = (( RP (today) / sma ( RP (today), n)) - 1 ) * 100
Where: RP = Standard Relative Performance indicator (see above) SMA = Simple moving average over n days. n = 52 for weekly charts, and n = 200 on daily charts