What does learning limited mean on Meta?

Meta names the usual causes. It says that generally an ad set becomes learning limited when it is limited by small audience size, low budget, low bid or cost control, high auction overlap, an infrequent optimisation event, or other issues such as running too many ads at the same time. For Shops ads, Meta says an ad set becomes learning limited when it hasn't generated a minimum of 17 purchases through your website and 5 through Meta after 7 days.

Meta lists its own fixes: combine ad sets and campaigns, expand your audience, raise your budget, raise your bid or cost control, and change your optimisation event to one that occurs more frequently, for example moving from purchases to add to basket. It says that if a learning limited ad set receives enough optimisation events since your last significant edit, it will move from Learning limited to Active.

The reading is ours rather than Meta's: nearly every cause on that list is about the setup, the audience, the budget, the bid and the number of ads and ad sets, rather than about the ads themselves, so a learning limited ad set is a question about structure before it is a question about creative. Meta also uses two words for the test. Its learning phase page says ad sets usually exit after about 50 results, and says learning limited is shown when an ad set isn't getting enough results to exit. Its learning limited page tests for about 50 optimisation events, and says you can add Optimisation events as a column in Ads Manager. Our reading, not Meta's: look at that column rather than assuming Results shows the same count.