MTCH – Volume consideration

Hi Pat -
Good morning!
Was watching MTCH today and saw it broke above our buy point on heavier volume (well above the 20 period Volume MA) , on the hourly, 30-min and 10-min charts. You passed on it because the volume was much lower than the falling price bars, which were quite high.
When considering the surge in volume, I have used the 20 or 50 period average volume in the past as a gauge for relative comparison. Looks like I need to add an additional rule.   :-)
How far back in time would you typically look at for relative volume comparison?
Thanks
Mike