Your Margins Are Shrinking and You Don't Know Why: Decision Tree

Why this matters

A margin that slips a point or two at a time is the most dangerous kind of problem, because nothing breaks. Every job still closes, the phone still rings, and the erosion hides inside a bottom line that stays positive right up until a slow month exposes it. By the time "we feel tight" becomes "we cannot make payroll," the leak has usually been running for a year. This tree walks the causes in the order they actually show up, from the one that catches most shops to the ones that take digging.

Start here: confirm the leak is real and name which margin

Before you hunt, pin down what is actually falling.

• Pull gross margin (the share of each sale left after the direct cost of the job: parts, the labor on it, and direct job costs) and compare the same stretch against last year, not against last month. Seasonal swing fools a month-to-month read.
• Separate gross margin from net margin (what is left after overhead too). A falling gross margin points at pricing or job cost. A healthy gross margin with a falling net margin points at overhead. That split alone cuts your search in half.

If the number is flat and you just feel poor, your problem may be cash, not margin. See related: Cash vs Profit Why They're Different.

If your prices have not moved in over a year

Start here, because this is the most common cause by a wide margin. Costs climb every year on their own: parts, wages, fuel, insurance. A price that held still did not hold still in real terms, it fell.

• Check the date of your last across-the-board increase. If it is more than a year back, your margin is eroding by simple neglect, and the fix is an annual price review, not a forensic hunt.
• If you raised recently and margin still slid, move down the tree.

If a specific cost jumped

Look at the direct cost side of the job.

• Pull your top parts and materials and compare unit cost against a year ago. A supplier who raised you a few points that you never passed through eats the difference straight out of margin. See related: Responding to a Supplier Price Increase.
• Check your loaded labor rate. Raises you gave (rightly) without a matching price move come out of margin.
• Fuel and truck costs creep the same way.

If costs are steady, the leak is not on the cost side. Keep going.

If the work you sell has shifted

Same prices, same costs, worse blend. This is mix shift, and it is easy to miss.

• Are you doing more of your thin-margin work and less of your fat-margin work than last year? A pile of low-margin jobs can drag the average down even when every single price is right.
• Track margin by job type to see it. See related: Tracking Margin by Job Type to Find the Leaks.

If discounts have crept in

Margin can leak one small giveaway at a time.

• Add up field discounts, "just this once" cuts, and standing discounts that quietly became a customer's permanent rate. Untracked discounting is invisible until you total it. See related: The Discount Discipline That Protects Your Margin.

If the hours are not making the invoice

The loss that never touches the price.

• Unbilled time: work performed and not captured on the ticket.
• Scope creep and freebies: the throw-in second trip, the "while I'm here."
• Callbacks and rework: you pay the labor twice and bill it once. A high comeback rate can put a healthy-looking job underwater.

If gross margin is fine but net margin is not

Then the job is earning and overhead is eating it.

• Did you add fixed cost (a truck, a hire, rent, insurance, software) without the volume to carry it? Overhead that grew faster than revenue drops net margin while gross margin looks perfect. See related: The Break-Even Number Every Owner Should Know.

The recap

1. Confirm the drop is real, year over year, and split gross from net.
2. Check price staleness first, it catches most shops.
3. Then job cost creep, then mix shift, then discount leakage, then unbilled time and rework.
4. If gross is healthy but net is not, look at overhead, not pricing.

Work it in that order and you will usually find the leak before the complicated causes.

References

• SBA, job costing and margin analysis for small business
• Standard managerial-accounting practice on gross versus net margin
• See related: Tracking Margin by Job Type to Find the Leaks, The Discount Discipline That Protects Your Margin, The Annual Price Review Every Shop Should Run