How we score cleaning services in the Columbia, SC area

What this page covers

The Columbia Cleaning Service Guide currently scores 300 cleaning businesses across the area, from one-person residential outfits to larger commercial crews. This page explains exactly how that score is built, why we weight things the way we do, and where the data runs thin. Nothing here is a secret formula: it's the same rubric applied to every business on the site.

The five signals, heaviest first

Each business gets a composite score from 0 to 100, built from five measured signals. Here they are in order of weight:

• Sentiment, 28%. A synthesis of what recent reviews actually say: the specific praise and the specific complaints, and whether the same issues keep coming up.
• Rating, 26%. The Google aggregate star rating.
• Volume, 20%. How many reviews a business has, log-scaled so 300 reviews doesn't get diluted the same as 6, but also so 6 reviews can't fake the confidence of 300.
• Recency, 15%. How recently customers have actually left reviews.
• Completeness, 11%. Whether phone number, website, hours, and address are all listed and current.

Why sentiment carries the most weight

A star average can hide a lot. Two cleaning companies can both sit at 4.5 stars, and one of them has a spread of happy, unrelated feedback while the other has a repeated thread of the same complaint, missed spots, no-shows, broken items, damage claims never resolved. The star number alone won't tell you that. Reading what recent reviews actually describe is the only way to catch a pattern like that before you book someone to be alone in your house or office. That's why sentiment is weighted higher than the star rating itself: it's the signal that explains the rating, not just repeats it.

Why the other signals matter

Rating still counts for a lot, 26%, because it's the fastest snapshot of how customers have felt overall. Volume matters because a 5.0 average from four reviews and a 4.7 average from 400 reviews are not the same claim, and log-scaling stops a tiny sample from outscoring a business with a long, proven track record. Recency matters separately from volume because a cleaning company can change: new ownership, new staff, a slip in quality control. Reviews from three years ago don't tell you much about who shows up at your door next week. Completeness is weighted lightest but still counts, because a business that lists a working phone number, real hours, and an address is easier to vet and easier to actually hire.

Where the confidence runs low

Some businesses on the guide have very few recent reviews. When that's the case, we say so directly on the listing: it's marked as a low-confidence score rather than presented with false certainty. A score built on three reviews from two years ago is not the same quality of evidence as one built on a few hundred recent ones, and we don't pretend otherwise.

We also don't republish review text wholesale. What you see on our listings is a synthesis of themes we found in recent reviews, and we link out to Google so you can read the original source yourself and form your own read on it.

What never changes the score

Scores come from this rubric and this data, full stop. They are not edited by hand after the fact. Where paid placement exists anywhere on the site, it is always labelled as paid and it never touches the score or the ranking math. Separately, if any list's picks or order were reviewed or adjusted by an editor rather than generated purely from the rubric, that page discloses it plainly. If you don't see that disclosure, the ranking came straight from the data.

Who runs this

The rankings and this methodology are maintained by Kai Ellis, Research Lead. Kai Ellis is responsible for the editorial oversight of how the guide is run and updated. For a current, ranked view of top providers built from this same rubric, see our best residential cleaning services list, or head back to the Columbia Cleaning Service Guide home page.