How to find out security with the most narrow bollinger band in X period.

for example: X=300

thanks for your supports.

Here's one way to do that for a 20-periods bollinger bands.

Open the Explorer.  Create the new exploration "  Most narrow Boll" (spaces are important).
Name ColA "Lowest".  Then put in this formula :
X:=300;
LLV(stdev(C,20),X)

Then run the exploration on your securities, look at the reports and double-click on the lowest column to sort the securities by the lowest value of bollinger bands.

That being said, it's not really usefull because security prices are different which means you can't compare the bollinger bands of a security to that of an other.  I'd create a column B named "ratio" with this formula :
X:=300;
LLV(StDev(C,20)/mov(StDev(C,20),100,E),X)

data,

thanks  for your useful supports.

Dear,
I'm a newbie looking for help. I'd like to explore securities with following criteria:
Bollinger bands: the narrowest the best (just compared with itself)
EMA (20 and 40): sideways and moving in nearly the same line
tks a lot

 Try coding like this:

{My variables}
a1:=BBandBot(C,20,S,4)-BBandTop(C,20,S,4);
a2:=Mov(C,20,E);
a3:=Mov(C,40,E);
{------------------------------------}
{Bollinger bands: the narrowest}
b1:=LLV(a1,100);
b2:=((a1-b1)/b1)*100;
b3:=(b2<5);
{------------------------------------}
{sideways}
c1:=HHV(a2,20)-LLV(a3,20);
c2:=c1<(0.1*C);
{------------------------------------}
{and moving in nearly the same line}
d1:=Mov(c1,20,S);
d2:=(Stdev(d1,20)<5);
b3*c2*d2

Write a sentence of what you want, break it out into segments, bracket the English,
then code each segment. This keeps you organized and it is easier to maintain and
change since the English is easier to read. Try plotting each b3,c2,d2 separately to
see if you want to change one, then just change the code.