I've written a function: 'bbw_expansion' that performs this check so that it can be incorporated in other projects of mine.
Example: bbw_expansion( , 5, 1.2) will return 'true' if 'bbw' is 20% greater (or more) compared to the last 5 periods.
The function returns: 'true' or 'false'
In true TradingView spirit, the author of this script has published it open-source, so traders can understand and verify it. Cheers to the author! You may use it for free, but reuse of this code in a publication is governed by House Rules. You can favorite it to use it on a chart.