Dropping the Google Analytics SDK into an app and recording key user actions can give good quantitive feedback and help streamline your user flows through design iteration.
To help plan the future direction, and ongoing success of the product, taking key user behaviour measurements over time can be a game changer.
Most mobile apps are found either by word of mouth, or by content discovery in the App Stores.
A trick here to measure the success of your marketing campaigns is to use a trackable redirect. For example, if I want to send someone to the App Store, I will actually link to a redirect URL, that automatically forwards the user to the App in the App Store, we can measure this.
By using a different redirect URLs for each campaign we can also measure the relative success of each campaign.
Install count can be gathered from the App Store analytics, a more important metric here is to measure what you might call an ‘Activation’. This could the user using the app for 30 seconds, or paging through a few screens. Many users will install apps never to actually use them, so this is a good measure of ‘First Impressions’
You will have to choose this based on the expectations you have for your users, but a good guide is 5 separate uses of the app and you have a user that found some initial value in the app.
At a couple of weeks we start to see app loyalty. The user might have made using the App a daily habit and will freely tell their friends about your awesome app. At this point you might also want to ask the user to review the app in the app store, or share via social media, which they will likely be more than willing.