How can I tell which SEO change made the difference?
Short answer
Only by making changes one at a time and measuring before and after each. If several things changed in the same month, nobody can separate their effects afterward. A clean test needs a baseline, one dated change, the same measurement repeated, and a check on what else moved in that window.
Telling which SEO (search engine optimization) change made the difference is possible only when the changes go in one at a time, with a measurement before and after each. If several things changed in the same month, nobody can separate them afterward. The site got new titles, the profile got a new category, ten reviews came in, and rankings rose. Any one of those could be the cause, or none of them, and no report can work backwards to find out.
What a clean test looks like
- Measure first. For local rankings I use a rank grid, the tool behind local rank tracking, which records your position from many points across your service area.
- Make one change, and write down the date and exactly what was changed.
- Leave alone anything else that could affect the same result.
- Measure again with the same searches from the same points. I re-measure about two weeks after a change.
- Keep the change if the result improved. Reverse it if the result got worse.
Skip step three and there’s no knowing which edit to credit, which is why only one thing changes at a time.
What else moves while you wait
Your change is never the only thing happening in those two weeks, so each test needs a check on the other possible causes.
| Other cause | How to check for it |
|---|---|
| A Google update | Google announces its larger updates publicly. See whether one fell inside your test window. |
| A competitor’s change | Look at whether the businesses around you moved as well, or only you. |
| Season and weather | Compare with the same weeks last year. This affects calls and clicks more than positions. |
| Your own business | New reviews, changed hours, a new phone number, or a website edit by someone else are all changes too. |
If every business in the results shifted on the same day, the cause is more likely Google than your edit.
Use a comparison where one exists
A result is easier to believe when something similar was left unchanged. Say a company has pages of the same kind for La Mesa, Santee and El Cajon. I can change the La Mesa page and leave the other two as they were. If La Mesa moves and the others stay put, the change is the likely cause. If all three move together, something else is going on.
This isn’t always possible. A business has one Google Business Profile, so a change to it has nothing to be compared with. There the before and after measurement is all the evidence there is, which is one more reason to change the profile one field at a time.
If several changes already went live together
Treat them as one bundle, record the date, and stop trying to split the credit. In theory you could reverse the changes one by one to see which mattered. In practice, undoing something that may be helping has a cost, and it’s rarely worth paying. The better course is to take a fresh baseline now and go forward one change at a time.
It also helps to keep a change log that everyone uses, because one edit that nobody mentioned can spoil a careful test. A web developer and an office manager may both have access to the site or the profile, and so may another vendor.
How sure you can be
Reasonably sure, never completely. Rankings wobble a little on their own, so a single before and after comparison is evidence, not proof. Confidence grows when the same change produces the same result on a second page, or when reversing it undoes the gain.
Rankings are also only the first link in the chain. Calls follow later and depend on more things, including your reviews and how quickly the phone is answered. I set the baseline for all of this in a Scientific SEO Audit, before anything changes.