Under the Standing Orders of the House of Representatives, a member of parliament can move a motion that the member who is speaking ‘be no longer heard’. This means the member must stop speaking. Members then vote on this motion. If the motion is passed, the member who was speaking must immediately resume their seat. This is commonly referred to as a 'gag motion' or 'gag order'.
Luckily gag orders use fairly standard words. As a proxy for how often gag orders are used we've used the number of hits in Hansard on those words: "I move: That the member be no longer heard".
We recognise this might slightly skew the numbers (because it's not impossible that the exact same words might be used in a slightly different context) but feel it is fair to use as an indicatator of how often gag orders are used. We've covered the two common formulations of "That the member no longer be heard" and "That the member be no longer heard".