It's even worse, as to count as a success, they would also need to show not just that they find something in more cases than without swat, but that the extra disturbance they cause when they don't find anything is worth it too.

Not to mention that what they find should be worth found too (e.g. some kid's stash of weed or some guy's coke is not to be counted among the "successes" -- you don't send a SWAT team for that, you send it to major dealers).