Cost per inquiry (CPI)
What you pay for each prospective-student inquiry from a paid channel.
Definition
Cost per inquiry is paid spend divided by the inquiries that spend produced. In much of higher ed, "inquiry" and "lead" are used interchangeably; where they're distinguished, an inquiry is the rawest form of interest — a form fill, an info request — before any qualification.
Like every cost metric, CPI is only as honest as its denominator: paid-source inquiries only, per channel, with gross or net spend labeled.
Why it matters
CPI is the earliest cost signal in the funnel — useful for spotting channel drift quickly, and dangerous when used alone, because cheap inquiries that never enroll are the most expensive kind.
How Pennant treats it
Pennant tracks the inquiry/lead stage as the top of the funnel with paid-source cost math, and pairs it with downstream CPE and LTE% so early signals are always read against eventual outcomes.