For a year we bought and sold Bangladesh as a single targeting unit, because that is the granularity every ad platform hands you. It was costing us about a third of our click-through rate.
Four different markets
Once we split delivery by city, the differences were not subtle. Peak viewing hours move by more than an hour between Dhaka and Sylhet. Language mix shifts. The categories that convert are not the same ones, and the creative that works in one is frequently the creative that is ignored in another.
A national campaign averages all of that into a number that describes nobody.
What splitting changed
| City | Share of delivery | CTR vs. national avg |
|---|---|---|
| Dhaka | 42% | +0.4pt |
| Chittagong | 28% | +1.1pt |
| Khulna | 18% | −0.3pt |
| Sylhet | 12% | +1.6pt |
Sylhet was the surprise. Smallest share, best response, and entirely invisible while it was averaged into a national figure.
The cost of the granularity
Four segments means four times the creative, four sets of pacing decisions and four ways for a campaign to go wrong. We do not offer it below a spend threshold, because under that it costs the advertiser more in production than it returns in performance.
Granularity you cannot afford to act on is just a longer report.
