Here's Leon Wilsons internal strength indicator converted.  It looks to be an 11 period RSI formula (really 21ema) with 3 period smoothing.    I changed it to a subtraction result as this is more useful, like hedge fund analysis.  ie. Long a number of strong stocks, Short a number of weak stocks.   The scan is set up the same way as above.

period:= input("Period",21,1);

smooth:= input("Smoothing",3,1);

symb := inputsymbol("Compare to", "XJO");

ind:=LoadSymbol(symb,C);

Up:=if(close>ref(close,-1),close-ref(close,-1),0);

Down:=if(ref(close,-1)>close,ref(close,-1)-close,0);

VALUE1:=100-(100/(1+(sum(up,period)/(sum(down+0.0000001,period)))));

Stock:=Ma(value1,smooth,E);

iUp:=if(ind>ref(ind,-1),ind-ref(ind,-1),0);

iDown:=if(ref(ind,-1)>ind,ref(ind,-1)-ind,0);

VALUE2:=100-(100/(1+(sum(iup,period)/(sum(idown+0.0000001,period)))));

Index:=Ma(value2,smooth,E);

Stock - Index;

From the resulting scan of the RSI comparison I did a screen capture of the strongest and weakest stock in the list from the ASX300.   Made another indicator to show all 3 RSI lines.   Red=Index, Green=Stock, Blue=difference or strength.   You can now see what is going on when they are subtracted.   The strongest stock is doing better than the index by 14% while the weakest is below -23%.   The red/green lines show the strongest one has been stronger than the index for about 2 weeks while the weakest one has been weaker for about 2 months. 

period:= input("Period",28,1);

symb := inputsymbol("Compare to", "XJO");

index:=LoadSymbol(symb,C);

[color=red]

[color=lime green]

stockRSI:= RSI(C,period);

stockRSI;

[color=blue]

period:= input("Period",28,1);

symb := inputsymbol("Compare to", "XJO");

index:=LoadSymbol(symb,C);

RSIrsc:=RSI(C,period) - RSI(index,period);

RSIrsc