What is IPM (installs per mille)?

What IPM measures

IPM isolates creative performance from media cost. Two creatives running on the same inventory at the same price will differ in IPM purely because one is more persuasive.

That makes it the standard metric for creative testing in user acquisition — it answers 'which creative works' without the confounding effect of what each cost to serve.

How it connects to CPI and eCPM

The three are algebraically linked, which is why IPM is a lever rather than just a diagnostic.

Higher IPM at a constant CPM means a lower CPI — the same spend buys more installs. From the publisher's side, higher IPM raises eCPM because the advertiser can afford to bid more for the same impressions.

This is why creative is the most reliable lever in user acquisition. Bid tuning fights an auction; a materially better creative changes the economics on both sides at once.

Why high IPM is not automatically good

IPM counts installs, not users. A creative that misrepresents the product will produce an excellent IPM and a cohort that uninstalls within a day.

The pattern is consistent enough to watch for: high IPM with poor day-1 retention means the creative is writing cheques the product does not cash. That is worse than a lower IPM, because you paid for installs, acquired negative sentiment, and polluted your cohort data.

Judge creative on IPM and retention together, never on IPM alone.