The short answer
When impressions and average position hold and clicks fall, the click-through rate has dropped: the same number of people see your result and fewer choose it. The usual causes are a change on the results page, a change in how your result reads, a shift in what people search for, or a change in the mix of queries.
Confirm it is the click-through rate
Clicks are impressions multiplied by click-through rate. If clicks fall and impressions do not, the click-through rate fell. Open Search Console, compare the last 28 days with the 28 days before, and look at clicks, impressions, click-through rate and position side by side, for the page and for the query you care about.
Check that the drop is not simply seasonal. Compare with the same weeks a year ago if you have the data. A page about a summer topic loses clicks in autumn at the same position.
Check the results page itself
Search for the query yourself, in the country and on the device your visitors use. Results pages change: an AI-generated overview above the results, a featured answer, a box of related questions, a map, video or shopping results can all push your result down the screen even when its rank number is unchanged.
Average position is a rank, not a place on the screen. A result in position 3 that sits below an answer box gets fewer clicks than the same rank did before. This is the most common reason for a drop that nothing on your own site explains.
Look at how your result reads
A search engine sometimes rewrites the title or the description it shows, and so do you when you change them. Look at what is shown today. A title that is cut off, a description that no longer matches what people search for, or a title that now looks like every other result can lower the click-through rate at the same rank.
If you changed the title or description recently, compare the click-through rate before and after for that page alone, not for the whole site.
- Is the title the one you wrote, or has it been replaced?
- Does the description answer the query, or is it a random piece of the page?
- Is the title longer than what is shown, so the end is cut off?
Split the data before you decide
A page-level number hides the pieces. Filter by query, device and country and see where the drop sits. Often it is concentrated in one group: one group of queries that a new results feature now answers, one device, one country.
Separate branded from non-branded queries. A drop in people searching for your name looks like a click-through problem but is a demand problem, and no change to the page will fix it.
What to do about each cause
Which action fits depends on what you found:
- A results feature takes the clicks: rewrite the result so that it offers what the feature does not, and accept that part of the traffic is gone for this query.
- Your title or description changed: restore or rewrite it, then measure that page for a few weeks.
- The mix of queries moved: look at the segments that grew and decide whether the page serves them.
- Demand dropped: the number is real, but it is not a problem to fix on the page.
Where the evidence stops
Measure the fix honestly
After you change something, compare the same page before and after in clicks per day, and note anything else that moved in the window. A rise after a rewrite can be seasonal or come from the results page changing back. State the measurement, then state how sure you are that your change is the reason.
In Lastmod
Lastmod looks for this pattern on your pages: it flags a page whose impressions and position hold while its click-through rate drops, shows the evidence, and says that a feature on the results page may be taking the clicks. It does not claim to know the cause, and it measures what a rewrite did afterwards with the same before-and-after comparison.