Time to target condition in the statutory biodiversity metric: the temporal multiplier, habitat created in advance, delay in starting, and what the workbook does not check

Every habitat a development creates or enhances is discounted for the years it will take to reach the condition claimed for it. The user guide calls the years time to target condition and the discount the temporal risk multiplier, and GOV.UK is the place to read how the guide wants them used. This page is about what the calculation tool does with them: where the standard years come from, how the two optional entries — habitat created in advance, delay in starting — change them, the table the multiplier is read from, the strings the cells write along the way, how the difficulty multiplier is tied to the same entries, what the small sites metric does instead, and what the free Quadrat check does and does not say. Every statement below was read from the formulas of the published workbooks named under Sources.

“The temporal risk multiplier represents the average time lag between the start of habitat creation or enhancement works and the target outcome. This is known as ‘time to target condition’.” — statutory biodiversity metric user guide, June 2026, p. 36

Where the standard years come from

In the statutory metric 1.0.4 the Standard time to target condition (years) cell on every creation and enhancement row is a lookup, not an entry. On the creation sheets it reads the hidden sheet G-4 Temporal multipliers, F3 to M135: one row per habitat, one column per target condition (Good, Fairly Good, Moderate, Fairly Poor, Poor, Condition Assessment N/A, N/A - Other). On the enhancement sheets it reads G-5 Enhancement Temporal, C4 to X136: one row per habitat, one column per start condition – target condition pair (Poor - Moderate, Lower Distinctiveness Habitat - Good, and so on). A cell in either table holds a whole number of years, the text 30+, or Not Possible ▲ where the workbook does not allow that habitat to be created in, or enhanced to, that condition. Those are the only three kinds of value either table holds (read cell by cell for this page).

The hedgerow creation sheet reads its own table, G-6 Hedgerow Data E3 to I15, by hedge type and condition; the watercourse creation sheet reads G-7 WaterC' Data O3 to O7 by watercourse type alone, with no condition dimension. (The hedgerow and watercourse enhancement sheets' standard-years lookups were not read for this page; their status, final-years and difficulty formulas were.) On the area enhancement sheets the lookup is skipped and Check Data ⚠ written instead when the row's distinctiveness-change or condition-change cell already reads Error — a trading problem comes first.

The two entries you can make

Beside the standard years sit two drop-downs, both offered on every creation and enhancement sheet of the statutory metric and both read from the same list, G-4 Temporal multipliers A42 to A73: the whole numbers 0 to 30, then 30+.

Columns as in metric 1.0.4; the first parcel row is 11 on A-2 and D-2 and 12 on every other sheet listed. The status column is headed Standard or adjusted time to target condition; the lookup and multiplier columns are hidden by the sheet's buttons.

The guide's data-entry appendix says what a blank means: left empty, “the metric will assume that the habitat will not be created in advance” and “that there will be no delay” (p. 85). The advance entry is the guide's creation in advance function, “the number of years habitat is created in advance of clearance of the habitat on-site (for example, when habitat banking is used)”; the delay entry is “the number of years the habitat is absent i.e. from clearance of the habitat to the start of habitat compensation for the loss” (p. 36).

What the status cell says, in the order the formula tests it

The status cell is where the workbook tells you how it read the two entries. On the area creation sheets (A-2 R, D-2 R) the tests run in this order and the first that matches wins:

1. Both the advance and the delay cell hold a number above zero → Error -both advance and delayed habitat creation ▲. The guide's troubleshooting table (p. 88): “Select either the advance creation or the delayed creation but not both. If two parcels of the same habitat are to be created in a staggered approach, then use two rows in the metric to present these separately.”
2. The habitat's distinctiveness score is zero → Standard time to target condition applied, whatever the two entries say. (A very low distinctiveness habitat scores zero units either way.)
3. The advance years are at least the standard years → Check details - Is there evidence that habitat has reached target condition? ⚠. This is the string that also switches the difficulty multiplier, below.
4. The advance years are at least the habitat's years to Poor condition (a hidden column — AE on A-2, AJ on D-2 — looks that up from the same creation table) → Check details - Is there evidence habitat creation started and the threshold for Poor condition reached? ⚠.
5. Any other advance above zero → Check details - Is there evidence habitat creation in place? ⚠.
6. A delay above zero → Check details- Delay in starting habitat in required condition? ⚠.
7. Otherwise Standard time to target condition applied.

The enhancement sheets and the hedgerow and watercourse sheets run a shorter version: both entries → the same Error ▲; advance at or above the standard years, with no delay → the reached target condition string; any other advance → Check details - Is there evidence habitat creation started/in place? ⚠; a delay → the Delay string; otherwise Standard. They have no Poor threshold test. Their reached target test also accepts the words Habitat already in target condition in the advance cell, but that text is not in the drop-down list, so it can only arrive by pasting.

Two of the strings have no symbol — Standard time to target condition applied and, on the difficulty side, Standard difficulty applied and Enhancement difficulty applied. They are the workbook's statement that nothing was adjusted; they are not flags. One more oddity of the published file: on the first parcel row of E-2 (off-site hedgerow creation, row 12) the Delay string is written without its ⚠; from row 13 down it has one.

One thing the area enhancement sheets do that the others do not. On A-3 and D-3, after the error and reached target tests, the status formula on each row checks whether the Required Action to Meet Trading Rules cell of the row above is empty (row 12 reads the header, which never is). Where it is — a filled row below an empty one — the cell writes nothing, so the started/in place, Delay and Standard … applied wordings do not appear on that row. The final years, the multiplier and the units are computed regardless; only the status text goes missing. The creation and linear sheets reference their own row. Whether that is intended is not for this page to say; it is what the formulas in the published 1.0.4 read.

The final years and the multiplier

The Final time to target condition (years) cell (A-2 S, A-3 AH and their equivalents) is the standard years plus the delay minus the advance, with these edges, read from the formula:

• If the status is the Error ▲ above, or the standard cell reads Not Possible ▲, the final cell writes Check Data ⚠ and the multiplier cell repeats it. The row's units cell then catches the error and writes nothing.
• An advance larger than the standard years gives 0 — the habitat is treated as already at target. On the hedgerow creation sheet an advance of 30+ also gives 0.
• A standard 30+ with no advance stays 30+; with an advance it becomes 30 minus the advance.
• A delay of 30+, or a total above 30, gives 30+.

The multiplier is then a plain lookup of the final years in G-4 Temporal multipliers A4 to C37. The table is 0.965 compounded: year 0 is 1, year 1 is 0.965, year 5 is 0.8368, year 10 is 0.7003, year 15 is 0.5860, year 20 is 0.4904, year 30 is 0.3434, year 31 is 0.3314, and the 30+ row is 0.3198 (0.965 to the power 32). The units formula multiplies by it: on creation rows, Habitat units delivered = area × distinctiveness score × condition score × strategic significance multiplier × final time to target multiplier × difficulty multiplier (A-2 Y = G × I × K × N × T × X). On enhancement rows (A-3 AN) only the gain between the baseline value and the proposed value is multiplied by the temporal and difficulty multipliers; the baseline value is added back undiscounted, and the whole is multiplied by the strategic significance multiplier (that page has the formula).

The 30-years note

Each creation and enhancement sheet carries one note cell in its header rows (A-2 N2, A-3 AD2, D-2 O2, D-3 AD2, B-2 M3, B-3 X2, E-2 O2, E-3 X2, C-2 V2, C-3 Y2, F-2 P2, F-3 Y2) that counts the 30+ values in the standard column and in the final column, and writes Note; Habitat selected has a time to target condition greater than 30 years. Non standard agreement may be required ⚠ when either count is above zero. It is one note for the sheet, not a mark on the row, and it does not say which row. On ten of the twelve sheets the string ends in a ⚠; on A-2 and F-2 it is written without one (and D-2, D-3, B-2, E-2, E-3, C-2, C-3 and F-3 add a full stop before the ⚠ that A-3 and B-3 do not) — small differences, but they decide what a string search finds. The workbook does nothing else with it: the 30+ multiplier of 0.3198 is applied and the units count. The guide's one rule on the subject is for woodland: “You may need to enter a legal agreement to secure woodland habitat for more than 30 years to allow time to meet the target woodland type and condition” (p. 19).

How the same entries move the difficulty multiplier

The difficulty multiplier is the second of the guide's three risk multipliers, and in the workbook it is tied to the temporal status cell. On the area creation sheets (A-2 U to X):

• Standard difficulty of creation (U) is the habitat's technical difficulty of creation from G-3 Multipliers, column B.
• Applied difficulty multiplier (V) reads the status: the reached target condition string → Low Difficulty - only applicable if all habitat created before losses ⚠; the started and the threshold for Poor string, for any habitat except six (Traditional orchards, Ornamental lake or pond, Ponds (non-priority habitat), Ruderal/Ephemeral, Tall forbs, Developed land; sealed surface) → Enhancement difficulty applied; otherwise Standard difficulty applied.
• Final difficulty of creation (W) is then the standard category where nothing was adjusted; the word Low where the Low Difficulty string stands and the advance is at least the standard years; and the habitat's technical difficulty of enhancement (G-3, column D) in the Enhancement difficulty case.
• Difficulty multiplier applied (X) looks the category up in G-3 P3 to Q6: Low 1, Medium 0.67, High 0.33, Very High 0.1.

So an advance of at least the standard years does two things at once: the temporal multiplier goes to 1 (zero years left), and the difficulty multiplier goes to 1 (Low), whatever the habitat's own difficulty category. The string beside it says the second only holds “if all habitat created before losses”, and that is all the string does — the workbook applies Low either way. The enhancement, hedgerow and watercourse sheets have the Low Difficulty switch and not the Enhancement difficulty one; the off-site watercourse creation sheet (F-2) writes the string with a No - prefix (No - Low Difficulty - only applicable if all habitat created before losses ⚠).

What the small sites metric does instead

The small sites metric 1.2.3 has no created-in-advance and no delay entry on any sheet, and no 30-years note. On its creation blocks (5. Area Habitats from row 40, 6. Hedges & Lines of Trees and 7. Watercourses from row 39) the Time to target condition/years cell (AE) looks the habitat and the targeted condition up in 10. Condition and Temporal, B6 to L103 — columns G to K hold the years to Moderate, Good, Poor, Condition Assessment N/A and N/A - Other — and the Time to target multiplier (AF) reads 11. Lists I47 to K80, the same 0.965 table with the same 30+ row at 0.3198. The targeted-condition drop-down offers the same five conditions for every habitat (11. Lists F47 to F51; the sheet shows the habitat's acceptable options in a column beside it), so a condition the habitat does not allow can be chosen. Where the lookup then says Not Possible (no symbol in this workbook) the multiplier lookup returns the text N/A, the units formula fails on it, and Habitat units created onsite (L) writes This intervention is not permitted within the SSM ▲ — that cell's catch-all for any error, which does not name the cause.

On the enhancement block (row 68 onward on sheet 5) the workbook decides from the habitat and the targeted habitat whether the row is a Condition enhancement (same habitat) or a Distinctiveness enhancement, reads the years from column L or M of 10. Condition and Temporal accordingly, marks the other N/A with a multiplier of 1, and discounts only the gain, as A-3 does. Difficulty categories come from 9. All Habitats + Multipliers and the four values from 11. Lists J35 to K38 (Low 1, Medium 0.67, High 0.33, Very High 0.1).

What the workbook does not check

• Evidence for an advance. The guide: “If you need to use these functions, you should provide justification and evidence to the relevant decision maker … referencing project phasing plans, additional agreements, showing that target condition of habitats created in advance have been met” (p. 37). No cell reads the User comments column; the Check details strings ask the question and the arithmetic goes ahead.
• Whether all the habitat was created before the losses. The Low Difficulty string names the condition; nothing tests it. Low is applied on the advance years alone.
• Phasing. The guide wants the two functions applied “on a phased basis” with a row per phase (p. 37); the workbook sees rows, not phases.
• Anything about the agreement. The 30-years note is a note. A 30+ row scores at 0.3198 and the headline figures include it without comment.
• Dates. Both entries are years, chosen from a list; no cell compares them with a survey date, a planning date or the Start sheet.

What the free check does with it

Drop the metric on the check page and Quadrat lists every cell string on the data-entry sheets that carries a ▲ or ⚠ — the five Check details strings, the Low Difficulty string, the Error ▲ for both entries at once, Check Data ⚠, Not Possible ▲ in a standard-years cell, and the 30-years note on the ten sheets where it carries a ⚠ — by sheet and cell, with the parcel's reference, habitat and User comments beside them. Any ▲ makes the verdict Not ready. The A-2 and F-2 notes and E-2's first-row Delay string, written without a symbol, are not listed.

One question the check asks that the workbook does not put on the row: for every parcel whose Final time to target condition (years) is above 30 or reads 30+, it lists an evidence gap asking how the habitat will be secured beyond the 30-year minimum of the agreement — the row-level version of the sheet's note. That question runs where the column is headed Final time to target condition (years), which is every creation and enhancement sheet of the statutory metric except F-2 (off-site watercourse creation), whose header reads Final time to target condition/years; the small sites metric heads its column Time to target condition/years. Neither variant is one the check reads, so on F-2 and on the small sites metric the question is not asked (a known gap, listed here rather than hidden). Quadrat never recalculates a year or a multiplier; it copies the workbook's stored values and reads the strings the workbook wrote.

Sources

The statutory biodiversity metric calculation tool 1.0.4 (macro-disabled workbook) and the small sites metric 1.2.3, both as published on GOV.UK's Statutory biodiversity metric tools and guides page and read on 4 October 2026: the columns, cells, lookup ranges, drop-down list and formulas named above are theirs, and the strings are quoted as the formulas write them, including the two notes without a ⚠. The statutory biodiversity metric user guide, June 2026 edition, p. 19 (woodland agreements beyond 30 years), pp. 36–37 (risk multipliers, time to target condition, advanced or delayed action, long construction timelines), p. 85 (the data-entry appendix) and p. 88 (the troubleshooting table). A later release of either workbook may move a cell or change a string; the version each statement rests on is named here so it can be checked. Quadrat is not affiliated with Defra or Natural England. If a cell on this page does not match the workbook in front of you, write to hello@quadrat.uk; replies are signed as Quadrat.