Per screen average (PSA)

A title on four thousand screens will out-gross a title on twelve, always, and the comparison says nothing. Divide by screen count and the picture inverts: a limited release opening in a handful of city-centre sites can post a per-screen average several times that of the week's number one.

That is the number distributors watch when deciding whether to expand a platform release. A strong PSA on twelve screens is the argument for a hundred and twenty.

For a cinema the same arithmetic runs internally. Your own average per screen, per session and per title is the number that tells you whether a run is working, independently of how many performances you gave it. A title with a modest gross across four daily performances may be doing better per show than one with a larger gross spread across ten.

PSA is easy to inflate. Open on very few screens, all of them in the highest-grossing locations in the country, and the average looks extraordinary — because the sample is chosen, not representative. Openings on a single screen in Manhattan have produced numbers that no wide release could approach and that predicted nothing about the wider run.

Treat it as a directional signal about demand density rather than a quality score, and read it together with the screen count that produced it. A PSA quoted without its denominator is a marketing number.