KPI Monitoring & Diagnosis: Why did your conversions and conversion rate change?

By Brad


General, Performance Analyzer

In our continuing series on KPI Monitoring & Diagnosis, today, we’re going to dig into investigating changes to your conversions. When you see large conversion changes, it can be a great day (when they are trending upwards) or a tough day full of analysis and changes (when they are going down).

As a reminder, this data doesn’t exist in a vacuum. It’s easiest to see this information in the context of other data in your account, which is why we suggest you use the Performance Analyzer found within Adalysis or Data Studio reports to see how these metrics are interrelated. You can see how these reports are stories or get a copy of the Data Studio report here.

What Affects Conversions?


When we see a change to conversions, there are only two possible high level reasons:

  • Your clicks went up or down
  • Your conversion rate changed

If your clicks changed and your conversion rates were the same, then you want to look at this article: Why Does the Number of Clicks You Receive Change Over Time?

If your conversion rates changed, then we need to start digging into the possible reasons.

Where to Start Diagnosing Conversion Changes

The first step is to isolate where the conversion changes are occuring. This can range from a single ad group to multiple campaigns. Of course, the changes could be positive or negative.


The second step is to look at Year over Year trending.


If you always have a change in conversions over that time period, you want to see if you were higher or lower than the previous year. If your conversions are down from the previous month, but higher than the previous year, then you need to ask yourself if it’s just a seasonality issue and everything is OK or if there’s a bigger problem.

The third step is to isolate the time when the conversions began to drop. Then look at the Change History tool inside of your Microsoft or Google Ads account to see if there were changes that caused the issues. As changes you make today might not cause immediate changes, you often want to look at the change history for 1-2 weeks before (and up to the day) when the conversions started to drop to see if there’s something you did that caused the changes.

Of course, also take into account any website changes that were made or changes to how conversions are being counted.

Lastly, we want to look at the Auction Insight data and our competitor’s ads to see if it’s not a change we made, but a change our competitors made that caused our conversions to decrease. In these cases, you might need to reposition your ads based upon competitor changes.

If none of these top level analysis shows you the primary reasons for the conversion drops, then we need to dig even deeper into the data to do our analysis.

Digging Even Deeper Into the Data

When we need to dig deeper into the data, the possibilities of what caused the issues start to expand significantly. The mantra is to ‘isolate and analyze’. You want to isolate exactly where the changes are happening, and it’s often easier to spot the trends in the most significant change areas. Find those ad groups or campaigns with the most significant drops, and then start your next set of analysis.

Keyword & Query Changes: Google made some considerable changes to match types over the past two years, so the first step is to start by looking at how your queries have changed with the match types changes. Please note that this might involve a lot of pivot table analysis, and this Intro to Pivot Tables video can help you get started with them.

Some of the top issues you might uncover in this analysis are:

  • Some top keywords have fallen in positions and aren’t shown as much
  • Some top search terms are now showing their ads from the wrong ad groups
  • Some top keywords were added to additional ad groups (easy to do with the standard workflows if you have duplicate query issues) and their conversion rates are lower in the new ad groups

If none of these uncover anything, then let’s move to the ads and the most common issues you might run into:

Other Oddities that Occur

Sometimes the reason for the changes is highly varied, and here are some other oddities we’ve seen:

Someone added a negative keyword list at the MCC level, which will not show up in your account change history, and conversions fell.

You were using automated bidding, and the system is starting to fail for one reason or another. The most common is a conversion tracking change or broken conversion codes for a few days that messed up the system’s data.

Run away scripts. A script started doing something, changing bid modifiers, adjusting budgets, or some other change that messed with how impressions were being served.

Broken links in the ads. When ads go to 404 pages, conversions suffer.

Negative press or negative press association with your company. I remember when a partner for BP Oil (who was responsible for the massive oil spill in the Gulf of Mexico several years ago) saw their conversion rates plummet, and they couldn’t’ figure out why. They featured BP Oil’s logo on their homepage. The negative association was the issue. They took down the logo, and everything went back to normal.

Audiences added with incorrect targeting. We’ve seen users add audiences as ‘targeting’ to their search campaigns without having a regular search campaign for non-audience members. Suddenly their conversions (and clicks) dropped since only a fraction of the previous users can now see the ad.

Anything that restricts or changes your targeting, can affect your conversions.

Putting Together a Plan

Once you have isolated the issues, then you need to fix them. Sometimes it’s as easy as adding search terms as match types, adding negative keywords, so Google shows your keywords accurately, pausing some ads, or doing some ad testing.

In other cases, you need to work with the website team for new pages, IT to fix broken pages, developers to fix scripts, or your client or agency to create ads that are positioned differently.

There will be times when your conversions are suddenly going up (this doesn’t have to be finding the bad, sometimes it’s isolating the good), and when you see positive trends, it’s useful to also isolate them so you can make sure they are sustainable. Find out why conversions are going up and use that information in other ad groups, from multi-ad group testing to useful landing page tests that you want to utilize across the account.

As long as you are automatically monitoring KPIs, such as conversion changes, then you’ll quickly be alerted to the change in trends so you can isolate, diagnose, and fix (or take advantage) of your conversion trends.

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One Comment

  • David Bosley

    Excellent post, Brad. I’ve followed many of your steps before but you have given me additional food for thought.

  • Leave a comment

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