Buying app installs is one of the few advertising markets where the headline metric can be manufactured almost at will, which is why cost per install is the least interesting number in any proposal. What matters is how many of those users open the app a week later, complete the action the business depends on, and are still there a month on. An agency that cannot talk fluently about retention and about how attribution actually works on mobile is selling volume.
Optimize to the event that matters, not the install
Networks optimize toward whatever event you send them, so an account reporting installs will find people who install. Define the event that represents real value, a completed booking, a subscription, a second session, and send that back. This usually requires a measurement partner configured properly, and it is the difference between a campaign that grows the business and one that grows a chart.
Understand what attribution can and cannot see now
Privacy frameworks on both major platforms limit user-level attribution, so a portion of performance arrives aggregated, delayed or modelled. That is not a supplier failing, it is the environment. What you should expect is an agency that explains which measurement they trust for which decision, and that uses incrementality tests rather than treating every reported conversion as caused.
Fraud checks belong in the contract
Click injection, click spamming and bot installs all exist and all inflate the numbers an agency is judged on. Ask what anti-fraud tooling is in use, who pays for it, what the rejection process with networks looks like, and whether you see rejected volumes. An agency that has never disputed a network invoice on fraud has either been extremely lucky or has not looked.
Creative volume is the performance lever
On the app networks, creative refresh rate is one of the strongest determinants of sustained performance, and playable or video formats usually need dedicated production. Ask how many new concepts a month are included, who makes them, and how variants are tested. A media-only agency attached to a starved creative pipeline will decay within a quarter.
Questions people ask about app advertising agency
What should we pay per install?
It is the wrong target. Work out what a retained, active user is worth over a sensible horizon and what proportion of installs become one, then derive an acceptable acquisition cost. Two campaigns with identical install costs can differ several-fold in value delivered.
How is an app agency usually paid?
A management fee or percentage of media, sometimes with a performance component on a defined post-install event. Tie any performance element to that event rather than to installs, and define who adjudicates it and from which measurement source.
Do we need a mobile measurement partner?
For any meaningful spend, yes. It is the neutral record between you and the networks, and disputes over attribution or fraud are difficult without one. Own the account and the contract yourself rather than having the agency hold it.
Should app store optimisation be part of the scope?
It should at least be coordinated, because the store listing converts the traffic the advertising buys and a poor one wastes media. Whether it sits with the same supplier matters less than that somebody owns the listing, tests it, and reports conversion from impression to install.