CPI (cost per install)

The average cost to acquire one app install.

Why it matters

CPI is a volume metric, not a value metric. On its own it says nothing about whether a user pays back, and optimising for the cheapest install usually buys the players least likely to spend. It is only useful next to LTV or ROAS.

How justtrack handles it

justtrack puts CPI next to cohort LTV and ROAS in the same view, so cheap installs cannot masquerade as good ones.

Related terms

• Lifetime value (LTV)
• ROAS (return on ad spend)
• CPA (cost per action)