Pete Bowen's site

I'm scared I'll break my campaign

Published April 2021. Last updated July 2026.

I got an email from a newish Google Ads person ...

... My biggest challenge is knowing if my changes are going to be winners or losers...

He went on to explain that this made him reluctant to try optimising the campaigns he manages.

I understand that. Changing a running campaign feels like sticking a screwdriver into a plane engine at 20 000 feet.

I'm a lot braver about making changes when I know exactly:

  • Why I’m making the change.
  • What I expect to see afterwards.
  • What a successful result looks like.
  • What I’ll do if I get a successful result.
  • What I’ll do if I don’t get a successful result.

I answer these questions before I make any major changes.

It might sound like extra work, but in practice it doesn’t take long. Let me show you how I do it using a couple of entries from my experiment log.

Example 1: Reducing the max CPC on a brand defence campaign.

Background: The client's competitors advertise on searches for his business. He wants his ad right at the top of the page when someone searches for his business by name.

The campaign uses the Target Impression Share bidding strategy, targeting the absolute top of the search results. The max CPC is $3. The Search Absolute Top Impression Rate was 98% over the last 30 days.

I'd like to reduce what it costs to defend the first page spot by lowering the max CPC. Here's what I wrote in my log before making the change. (Confession: I've tidied the wording a little.)

Log entry:

I expect that lowering the max CPC from $3 to $1 will reduce Search Absolute Top Impression Share and reduce the average CPC. If the Search Absolute Top Impression Rate stays above 85% over the next 30 days I’ll keep this change. Otherwise I’ll increase the max CPC from $1 to $2 and see how that affects the Search Absolute Top Impression Rate.

Example 2: Tweaking a lead generation campaign that uses the TargetCPA bidding strategy.

Background: I changed the bidding strategy from max clicks where the average CPA was $28 to TargetCPA with a target CPA of $22.

Log entry:

Target CPA of $22 achieved over the last 30 days but total number of conversions went down and budget wasn’t all spent. I’m going to raise the target CPA to $25. I expect to see the actual CPA at about $25 and the number of conversions increase. If the number of conversions in the next 30 days is > 300 I’ll keep this change. Else revert to max clicks.

I record keep my logs in a purpose-built tool, but it's probably overkill. A notebook, Google docs, Trello etc works fine for the first few hundred experiments.

Most Google Ads Problems Aren't Google Ads Problems
If my writing resonates with you, I'd like to give you a copy of my book, Profitable Google Ads. The book was written for business owners, but many PPC professionals have found it valuable too.
Before you download it, what describes you best?

Related articles

Why a Google Ads account audit Isn't enough

Testing Google Ads for an RV Campground

Why negative keywords are becoming less effective in Google Ads

What’s the right bidding strategy for a brand new Google Ads account?

You can't run profitable Google Ads if your pipes are leaking

The campaign looks good but the ads aren't profitable

Topics you'll find on this site

Agency insights

Thoughts and lessons on client selection, burnout, pricing, and modernising legacy accounts, from someone who's run a Google Ads for years.

Conversion tracking

Understand what happens after someone clicks your advert. Subjects include offline conversions, CRM integration, attribution, auditability and marketing instrumentation.

Essays and thinking

Articles about marketing, engineering, AI and problem solving that don't fit neatly into the other topics. These are some of the ideas and experiences that have shaped how I think.

Google Ads for lead generation

Learn how to use Google Ads to generate profitable leads. Subjects include campaign strategy, bidding, targeting, optimisation and the challenges of running lead generation campaigns.

Landing pages

Things I've learned about high-converting landing pages. Subjects include copywriting, page structure, forms, trust, conversion rate optimisation and user experience.

Lead quality

Understand why some leads become customers while others don't. Subjects include diagnosing poor leads, qualification, filtering junk leads and improving the feedback you send to Google Ads.

Sales Process

What happens after a lead has been generated determines if Google Ads is profitable. Subjects include first contact, follow-up, quoting, lead nurturing and turning more enquiries into customers.