Blog · Wallet share and penetration · Construction and building materials
The complete category share by trade calculation on five trade accounts at one branch, small enough to check by hand: each account's spend by category from the ledger, its trade from the master, confirmed or inferred, the trade norm per category from the full-supply accounts of that trade, norm penetration, category share against the norm, the gap per category valued at the account's spend, the untyped account excluded and counted, and the assertion that category spend sums to the ledger, so a reader can reproduce every figure and then run it on their own ledger and account master.
Category share by trade is a share per category against a norm that depends on what the account is, and on five accounts it can be done by hand. This page works the spend, the trades, the norms, the expected categories, the gaps, the untyped account and the assertion.
Categories: pipe and fittings (PF), cable and accessories (CA), timber and sheet (TS), aggregates (AG).
| Account | Trade, source | Spend | PF | CA | TS | AG |
|---|---|---|---|---|---|---|
| 1 | General builder, confirmed | £84,000 | £6,700 | £5,000 | £10,100 | £0 |
| 2 | General builder, confirmed | £52,000 | £4,200 | £3,100 | £17,200 | £9,400 |
| 3 | Plumber, confirmed | £41,000 | £17,200 | £1,200 | £2,500 | £800 |
| 4 | Electrician, inferred | £22,000 | £400 | £12,100 | £900 | £0 |
| 5 | Untyped | £60,000 | £9,000 | £8,000 | £14,000 | £6,000 |
| Total | £259,000 |
Branch ledger for these five: £259,000. Category columns per account sum to the account's spend, less tools and consumables and other categories not shown. Assertion on the shown categories: each account's four categories are within its spend.
| Category | Builder: share, penetration | Plumber | Electrician |
|---|---|---|---|
| PF | 8%, 70% | 41%, 98% | 2%, 20% |
| CA | 6%, 65% | 3%, 30% | 55%, 99% |
| TS | 32%, 97% | 6%, 40% | 4%, 30% |
| AG | 18%, 92% | 2%, 20% | 1%, 10% |
Expected category: norm penetration at or above 50 percent.
Share = category spend ÷ account spend; gap = (norm share − share) × account spend, for expected categories, floored at zero
| Account | Category | Share | Norm | Expected? | Gap |
|---|---|---|---|---|---|
| 1 | TS | 12% | 32% | Yes | £16,800 |
| 1 | AG | 0% | 18% | Yes | £15,100 |
| 1 | PF | 8% | 8% | Yes | £0 |
| 1 | CA | 6% | 6% | Yes | £0 |
| 2 | TS | 33% | 32% | Yes | £0 |
| 2 | AG | 18% | 18% | Yes | £0 |
| 3 | PF | 42% | 41% | Yes | £0 |
| 3 | TS, AG, CA | Not expected of a plumber | none | ||
| 4 | CA | 55% | 55% | Yes | £0 |
| 4 | AG | 0% | 1% | Not expected of an electrician | none |
| 5 | Untyped | unknown |
| Rank | Account | Trade | Gap | Categories |
|---|---|---|---|---|
| 1 | 1 | General builder | £31,900 | Timber and sheet £16,800; aggregates £15,100 |
Account 1 is a builder buying no aggregates and a third of the timber a builder buys, from a merchant that sells both. Account 2, the same trade, is at norm on both. Account 4's missing aggregates are not a gap. Account 5's value at norm is unknown until it is typed.
| Branch | Accounts | Confirmed | Inferred | Untyped |
|---|---|---|---|---|
| This one | 5 | 3 | 1 | 1 |
Branch average as the norm. The average aggregates share across the five is 6 percent; account 4 is told to buy aggregates and account 1's gap reads £5,000.
Untyped defaulted to builder. Account 5's £60,000 gets a builder's gaps it may not have.
Inferred treated as confirmed. Account 4 may be a builder in its first month who has only bought cable so far.
Low-penetration categories expected. The plumber told to buy timber.
The same norms per trade from every full-supply account, the same expected floor, the same gaps, per branch, with the trade data quality beside it. Covirage runs it on the ledger and the account master every month. The category share by trade guide covers the measure, and the expected basket glossary entry covers the same idea on a foodservice desk.
Because only one in ten electricians buys aggregates from the merchant, so an electrician without them is normal. The norm penetration floor, half the trade's accounts, decides which categories are expected of a trade, and aggregates are not expected of electricians.
From the account's own basket against the trade norms: an account whose basket is 55 percent cable and accessories looks like an electrician. It is labelled inferred, its gaps are shown with that label, and the branch confirms it at the counter.
Spend, no trade, no gaps, and a count. A branch with a fifth of its accounts untyped is building its list on four fifths. Typing the account is a question at the counter, and the row says the value at norm is unknown until then.