Has the Bollinger Band Width indicator of  V12 been validated?  I'm receiving what appears to be erroneous output for a 50 bar 2 deviation setting when viewed against the ROST symbol.

If it has been validated, can you provide a link which explains how to interpret the output?

Yes, the calculations for the Bollinger Bandwith are correct.

It is simple to verify as the Bollinger Bandwidth Indicator is the ratio of the difference between the Upper Bollinger Band and Lower Bollinger Band to the Centerline (which is a Moving Average of the same Period as the Bollinger Band).

So you could add a Custom PCF Indicator to the same pane as the Bollinger Bandwidth 50, 2.00 indicator using the following formula:

4 * SQR(ABS(C ^ 2 + C1 ^ 2 + C2 ^ 2 + C3 ^ 2 + C4 ^ 2 + C5 ^ 2 + C6 ^ 2 + C7 ^ 2 + C8 ^ 2 + C9 ^ 2 + C10 ^ 2 + C11 ^ 2 + C12 ^ 2 + C13 ^ 2 + C14 ^ 2 + C15 ^ 2 + C16 ^ 2 + C17 ^ 2 + C18 ^ 2 + C19 ^ 2 + C20 ^ 2 + C21 ^ 2 + C22 ^ 2 + C23 ^ 2 + C24 ^ 2 + C25 ^ 2 + C26 ^ 2 + C27 ^ 2 + C28 ^ 2 + C29 ^ 2 + C30 ^ 2 + C31 ^ 2 + C32 ^ 2 + C33 ^ 2 + C34 ^ 2 + C35 ^ 2 + C36 ^ 2 + C37 ^ 2 + C38 ^ 2 + C39 ^ 2 + C40 ^ 2 + C41 ^ 2 + C42 ^ 2 + C43 ^ 2 + C44 ^ 2 + C45 ^ 2 + C46 ^ 2 + C47 ^ 2 + C48 ^ 2 + C49 ^ 2 - 50 * AVGC50 ^ 2) / 50) / AVGC50

And it would line up with the Bollinger Bandwidth indicator and display the same values.

Please note the indicator we discussed in the Price vs Bollinger band indicator was a Bollinger Band %B indicator, not a Bollinger Bandwidth indicator.

Thank you.   Yes I realized I changed indicators on you...

I will play with your formula to see why my results are looking unreasonable.

You're welcome.