It involves marketing your app to potential users. ROI is typically measured as the cost-per-install against the lifetime customer value.
ROI = (Gain From Investment – Cost Of Investment) / Cost Of Investment
Also, please find the important ROI metrics below,
CPI = Ad Spend / Number Of New Installs Which Come From A Campaign
LTV (Lifetime Value) = (1 + K) X ARPU
ARPU (Average Revenue Per User) = Total Revenue / Number Of Users