Shared negative keyword lists: one master list or per-campaign negatives?

A lot of accounts attach one shared negative list to every Search campaign, and it looks tidy right up until it causes trouble. A term that's junk for one campaign can be exactly what another one needs. Say a home services account runs an "emergency repair" campaign and a "seasonal maintenance" campaign. Blocking "DIY" and "cheap" everywhere is probably fine. But if someone adds "free estimate" or "quote" to tighten up the emergency campaign, the maintenance campaign quietly loses its best intent traffic, and nobody notices because the reports look cleaner.

I'd keep a small shared list for true junk and put campaign-specific negatives on each campaign. Shared lists get forgotten, and that's usually where the problems start.

Agreed on the split. I'd keep shared lists to terms that are never buyer intent in any campaign, like job-seeker traffic ("jobs", "salary") or competitor-brand junk you've already decided to exclude. Anything that depends on the offer (free, quote, cheap, DIY) belongs at campaign level, because the same word can mean different things to different campaigns.

There's one practical catch. A shared list attached at account level applies everywhere, so a single careless addition hits every campaign at once. Keeping the list tiny makes that risk much smaller.

Agreed on keeping it tiny. My rule of thumb is that a term only goes on the shared list if you can say it's junk for every campaign, including ones you haven't built yet. If you hesitate even for a second, put it on a single campaign instead. Shared lists tend to get edited by someone who only has one campaign in mind, so the list should only hold terms nobody would ever want back. And before you add one, check the search terms report for each live campaign. It shows what the term would actually block, and that's usually more than you expected.

The search terms report check is the part most people skip. A shared list only affects Performance Max and Demand Gen if you attach it to those campaigns, so look at which campaign types a list is actually applied to before you edit it. Otherwise you can end up blocking a term you thought was only hitting Search.

Marco's right to check where a list is attached, and it's easy to forget a shared list stays live after the campaigns it was built for have changed. But the search terms report doesn't show what a negative would block, Sasha. It shows what already matched. A phrase-match negative like "free" will also block queries that haven't come in yet, and the report can't tell you how many of those would have been buyers. So a clean-looking list of past queries can still hide a lot of future damage. For each term, I'd pull the matched queries for the campaigns that will actually be affected and ask whether any of them would have converted. With a term like "free", the answer is usually yes for one campaign and no for another, which is exactly why it belongs at campaign level.