Every shop manager gets handed a report full of acronyms and is expected to know which ones matter. Most of them do not, individually. What matters is understanding what each number is actually measuring, because a KPI you do not understand is a number you will chase in the wrong direction.
Here are the ones that run a service shop, and what each one is really telling you.
Average repair order (ARO)
What it is: total sales divided by the number of repair orders. The average amount of work on each car that comes through.
What it tells you: whether you are finding and selling the work that is actually on the vehicles. A shop with a low ARO is usually not inspecting properly, not presenting findings well, or both.
How it misleads: ARO rises if you turn away small jobs, and it rises if one large job lands in a slow week. Look at it as a trend across a month, not a day, and look at it alongside car count. An ARO that climbed while car count fell is not a win.
Car count
What it is: how many vehicles you serviced in the period.
What it tells you: the health of the front of your funnel — marketing, reputation, phone handling, retention. ARO measures what you do with a car once it is here. Car count measures whether cars arrive.
These two multiply. Sales are car count times ARO, which means a shop can grow by getting more cars, doing more per car, or both — and the two levers are pulled by completely different people doing completely different things.
Hours per repair order
What it is: billed labour hours divided by repair orders.
What it tells you: the depth of work per visit, stripped of parts pricing. It is a cleaner read on selling and inspection quality than ARO, because it does not move when parts costs change.
If ARO is up but hours per RO is flat, you are selling more parts, not more work. That is worth knowing.
Effective labour rate (ELR)
What it is: total labour sales divided by billed labour hours — what you actually earn per hour, as opposed to what your door rate says.
What it tells you: how much of your posted rate you are actually collecting. ELR is almost always below the door rate, and the gap is made up of discounts, coupons, warranty work at reduced rates, and hours given away.
This is the most quietly informative number on the report. A shop can be busy, hitting car count, and still failing because it is discounting away a large share of every hour. If your ELR is well below your door rate, the problem is not volume.
Technician efficiency and productivity
These two get used interchangeably and they measure different things.
Efficiency is billed hours divided by hours actually spent on those jobs. It measures how fast a technician works relative to the labour guide.
Productivity is billed hours divided by hours the technician was at the shop. It measures how much of their paid day turned into billed work.
The distinction matters enormously for diagnosis. A technician with high efficiency and low productivity is fast but idle — that is a dispatch, workflow or car count problem, and it is your problem, not theirs. Low efficiency with high productivity means they are busy all day but slow on the jobs, which is a training or job-mix issue.
Treating the first case as a technician performance problem is one of the most common management errors in the trade.
Closing ratio
What it is: the proportion of recommended work that gets approved — measured in dollars, in hours, or by item count.
What it tells you: how well findings are being presented, and how much the customer trusts the recommendation.
How it misleads: a very high closing ratio is not automatically good. It often means the shop is only recommending the obvious, safe items and not doing a thorough inspection. A very low one means you are finding plenty and communicating none of it. Read it next to how many items are being recommended per RO.
Gross profit, split by parts and labour
What it is: revenue minus direct cost, expressed as a percentage — calculated separately for parts and for labour.
Why the split matters: a combined number hides where the problem is. Parts gross erodes through inconsistent matrix pricing and supplier cost creep. Labour gross erodes through discounting, comebacks and giveaway hours.
They have entirely different fixes, so track them apart.
Comeback rate
What it is: repeat visits for the same concern, as a share of total repair orders.
What it tells you: the real cost of speed. Comebacks consume a bay, a technician, parts, and a customer relationship, and they usually appear on no report at all because they are billed at zero.
If you track one thing on this list that you are not tracking today, make it this one.
Customer retention
What it is: the share of customers who return within a defined window.
What it tells you: whether the shop is building anything. Acquiring a new customer costs far more than keeping one, so a shop with strong car count and weak retention is running to stand still — and the marketing spend that hides it will eventually stop working.
How to actually use these
Do not chase all nine. Pick the two that describe your current constraint and work on those.
Low car count is a marketing, phone and retention problem. Low ARO with healthy car count is an inspection and presentation problem. Low ELR is a discounting and pricing problem. Low productivity with good efficiency is a workflow problem you own.
The number is never the goal. It is a pointer to where the work is.
Related reading
- Raising ARO Without Overselling
- Coaching Advisors to Sell: A Shop Manager’s Guide
- 10 Ways Auto Repair Shops Quietly Lose Gross Profit
ARNAZ Group runs 10 Midas shops across Wayne, Oakland and Washtenaw counties. Our shop managers own their numbers and are paid accordingly. See our shop manager openings.