---
id: 2026-05-26T19:13:25-0400
title: 2026-05-26 19:13:25
tags: []
daily: "[[2026-05-26]]"
---
# 2026-05-26 19:13:25

## Number of Units as an Estimate Parameter

In [[pdi-estimating]] there is an expectation
that certain project costs are best predicted
as a function of the number of dwelling/sleeping units.
Some of these are quite unintuitive,
especially feeders and switchgear.

As a primarily residential contractor with visions of breaking out,
it is vital that we develop more market agnostic heuristics.
To my investigation,
preference for unit count over area as a parameter
may never be well founded,
and is perhaps evidence of a correlation assumed rather than measured.

The relationship between unit count and total building area
is in the concept of **building efficiency**,
the ratio of **net saleable area** to **gross area**.

When we see correlation in cost and unit count
what we're actually observing
is the correlation in cost and gross area,
through the correlation in gross area and unit count.