How to diagnose pMax campaigns for ecommerce brands

If you run with Performance Max campaigns you know the stressful feeling of seeing it break – Learn how to diagnose it here

We know and hate the feeling of a Performance Max campaign failing to deliver results to a business, and the stress that comes with it 

In stressful situations like this, you tend to make unwise decisions which eventually lead to a larger decline in sales 

What you essentially need is a guide checklist for when (yes “when”, not “if” performance and sales decline, and this is exactly what I’ll give you today 

Non-pMax specific

Sometimes it’s not the pMax itself that is the issue, it’s it’s somewhat common that it’s a “non-pMax” issue that causes your pMax to tank. Here’s the checklist I always use for when things go south 

Check conversion cycle/conversion lag 

Do your products have a long consideration cycle (time between seeing a product to buying it)? 
If yes, you have to look at performance in a broader data window than the last 7/14 days. Navigate to Tools & Setting > Attribution > Path Analysis to get an idea of your conversion cycle

Tracking issues 

Tracking can break from time to time due to a change in checkout experience or scripts being deleted from the back end, so a complete tracking checkout is also important to perform when pMax campaigns decrease in performance 

Correct tracking is essential for Smart Bidding to do its job and hit your targets, so if tracking breaks, Google loses sight of how your campaigns perform in general - pretty self-explanatory, but tracking checkups are important to perform 

Product disapprovals/Feed issues 

One of the more common things to happen when a pMax campaign specifically tanks or decreases in performance is due to a hero product (an SKU that has performed great for a long time) being disapproved or sold out. 

This is why the check of product disapprovals/availability is one of the first things you should check when performance decreases 

The way Google’s algorithm works is if Google finds 4-5 SKUs within a pMax campaign that enables the campaign to hit the tROAS set by the end user, Google will move 90% of the spend toward those SKUs to maintain performance above or near the tROAS - if one (or more) of those SKUs are being unavailable for the campaign performance will decrease quite significantly as Google now tries to find new SKUs that could enable the campaign to hit the tROAS

Checkout experience in back-end 

This is a big one and could be tied together when doing the tracking checkup, but when things increase in performance, make sure to go through your own checkout flow as a customer and see if there is an issue with the steps a customer needs to take in order to purchase a product from your store. 

It could be issued in relation to: 

  • Internal payment processors' errors
  • People are not being sent to checkout after pressing “order now” 

Sales period/offers ending 

Yes - I’ve included this checkpoint for checking if a sales period has ended. Allow me to explain why this is a checkpoint. 

I’ve had two cases where performance was super strong for months, and then out of nowhere - boom - performance down +40% overnight 

Long story short - turns out it was due to an offer being unpublished after being kinda forgotten 

The offers were SKU specific and those SKUs were bestsellers with the offer on, but sales decreased dramatically after the offer was taken down

Learned my lesson from these 2 cases, and now I use marketing calendars on all my projects, i recommend you do the same, and avoid the stressful diagnosis of performance being down when it turns out to be a human-created issue of not knowing that the offer was driving strong performance 

pMax specific

Check budget allocation 

You have two options for evaluating budget allocation within your pMax campaign

Mike Rhodes pMax reporting script - Find it here
With this script, you get the complete overview of what happens inside your pMax including how your budget is being spent across the networks.

Within the Google Ads interface

With a custom report, you can also see how spend is being allocated 

Select Report > Pre-defined reports > Shopping > Shopping – MC ID 

Then filter by pMax campaigns 

Then try to notice the difference in overall cost when you remove the “MC -ID” row - this difference in cost is what’s being spent on search/display/video

its common that i can tie the reason for a drop in pMax performance to the spend allocation leaning more towards search/display than shopping 

Solutions for that is: 

  1. If you run with a feed/shopping only pMax = disable ACA (automatically created assets)
  2. If you run with a fully built pMax (with headlines, descriptions, images, and videos) = re-vert the pMax into a feed/shopping only pMax with no assets.

Check landing page (custom report) 

With “Automatically Created Assets” enabled you also allow your pMax to use your landing pages as content for creating Dynamic Search Ads 

If you don’t work proactively with excluding non-sales landing pages (like FAQ, Refund policies, Cookie policies, etc) you give Google the ability to use those landing pages for creating ads 

Check which landing pages get traffic and exclude them if they get +100 clicks with no sales or bad ROAS 

If you see a FAQ page getting a lot of traffic with no conversion = exclude it from all pMax campaigns in the campaign settings 

Disclaimer: This is not me saying that all non-sales landing pages will perform badly, but me saying that you need to monitor how pMax spends on those landing pages - if you see something you don't like > Exclude the landing page. 

Asset group disapprovals (if pMax is fully built) 

Google uses AI for scanning content on an asset group level, and it can happen that certain headlines, descriptions, images and videos gets disapproved by mistake from one day to another 

It’s less common for me, but have tried in some instances that images have been disapproved sometime after being launched due to promotional texts

The solution is pretty straightforward - if you don't agree with the decision, you simply appeal, or simple edit the image and re-upload it again 

Badabum bada bing 

Negative keywords + brand exclusions added recently 

The last checkpoint of the checklist is about human-made exclusions 

Added a negative keyword list and brand exclusions is a hot topic in today's pMax discussions, and using them wrongly can affect your pMax performance in a negative way 

If performance has been bad since adding a brand exclusion list you need to dig into other parts of your Google Ads account and determine if the decline in performance is picked up elsewhere - for example, going back to your brand search campaign and see if you have gotten an uplift in conversion since adding your brand exclusion list. If that is the case - move on and accept that the decline is now normal for now in your pMax for the next few weeks and adjust targets accordingly 

If the decline in performance comes after adding a negative keyword list, I would take a closer look of the negative keywords within the negative keyword list and see if some of the terms (found in insights) is closely related to keywords that have been excluded in the negative keyword list.  

Want to work with us?

Partner with Ecommerce Google Ads Growth Experts!

Apply to work with us! We prioritize working with businesses generating +€20,000+ monthly revenue and wanting to scale, to ensure maximum impact.

For aspiring businesses that generates below €20.000, check out our Google Ads Consulting Program