Forecasting jobs in an Economic Impact Assessment

The jobs number in an Economic Impact Assessment is the figure that ends up in the committee report, and it is the figure officers test hardest. An economic impact assessment jobs forecast is built by applying employment densities to the proposed floorspace, separating construction from operation, and then adjusting the gross figure down for leakage, displacement and substitution before adding back a multiplier. Skip the adjustments and you produce a number that a consultee can take apart in a paragraph.

What the forecast is used for

Three audiences read it, and they want different things.

The case officer wants a defensible figure to weigh in the planning balance against whatever harm the scheme causes. Members want something they can repeat. An objector wants to find the assumption that inflates it.

The forecast also feeds other documents. Section 106 negotiations on local employment and training commitments start from it, and a Viability Assessment may use the same floorspace assumptions for different purposes, so the two have to agree.

Write the forecast knowing it will be quoted out of context. That argues for a conservative headline figure with the workings shown, rather than a large one with the caveats buried.

Employment density assumptions by use

The starting point is floorspace divided by an employment density, expressed as floor area per full-time equivalent job. Densities differ sharply between uses, and they differ within a use class too.

Offices, light industrial, warehousing, retail, food and beverage, hotels and health and care uses all have their own published densities, and warehousing in particular has a wide range because a highly automated distribution shed and a manual pick operation occupy the same building type with different staffing.

Three rules keep this honest.

Use the same published source throughout and name it, with its edition. Mixing densities from different sources produces an internally inconsistent answer.

Use net internal area or gross internal area consistently, matching whatever basis the density source uses. This is the most common technical error and it can move the answer by a wide margin.

Where the end occupier is known, use their actual staffing rather than a density. A named occupier with a staffing plan beats any published average, and officers accept it readily.

Construction and operational phases, kept apart

Construction employment is temporary and is measured in person-years, meaning one job sustained for one year. Operational employment is ongoing and measured in full-time equivalents.

Reporting them as a single total is misleading and officers will say so. Present them as separate lines, state the construction period, and be explicit that construction employment ends when the building is finished.

Construction employment is normally derived from the construction cost using published output-per-worker relationships rather than from floorspace. Say which relationship you used.

Phasing matters on larger schemes. A ten-year build programme does not produce its construction employment in year one, and presenting the total as though it does overstates the immediate benefit. Set out the profile by phase where the scheme is phased, because members weighing a decision now care about what happens in the next few years.

Gross to net adjustments

This is the section that separates a credible assessment from a brochure. The standard additionality framework works through a sequence of deductions.

Take them in order and show each step as a separate line with the percentage applied and its source. A table taking the gross figure down to net additional jobs, with a row per adjustment, is what a reviewer wants to see.

Percentages should be sourced rather than assumed. Published evaluation evidence gives ranges for leakage and displacement by sector and by intervention type, and an assessment that cites a range and explains where in it this scheme sits is far stronger than one that applies a round number without comment.

Displacement is the one that bites on retail and leisure schemes, where much of the trade is drawn from existing operators in the same catchment. A scheme claiming several hundred net new jobs in a town with a static population needs to explain where the spending comes from, and the Retail Impact Assessment should be consistent with that explanation.

Substitution is the one that bites on relocations. A firm moving from a nearby unit into a new building creates very few net additional jobs in the local authority area, whatever the floorspace suggests.

Study area and why it changes the answer

Every adjustment depends on the geography. Leakage measured against a district boundary is much higher than leakage measured against a travel to work area.

Choose the study area first, justify it by reference to commuting patterns rather than administrative convenience, and apply it consistently. Where the authority has a preferred geography, use it, and present a second set of figures for your preferred area if it helps.

Stating two geographies openly is more persuasive than quietly choosing the flattering one.

Local employment commitments

Most section 106 packages on major commercial schemes include something on local labour, apprenticeships or training during construction, and sometimes during operation.

Keep the commitment measurable. A percentage of the construction workforce recruited within a defined area, a number of apprenticeship starts, or a contribution towards a local employment brokerage are all enforceable. A commitment to use reasonable endeavours to support local employment is not.

The Economic Impact Assessment should set the commitment against the forecast, so that members can see the relationship between the jobs claimed and the jobs secured.

Presenting figures that survive scrutiny

1. Lead with the net additional operational figure, not the gross construction figure.
2. Put the gross to net table in the main text rather than an appendix.
3. Name every source with its edition and date.
4. State the study area and the assumed construction period next to the headline numbers.
5. Round sensibly and avoid false precision, because a figure quoted to the nearest job implies an accuracy nobody has.
6. Include a short paragraph on what would change the answer.

Point six is the one most reports omit and the one that builds credibility. An assessment that says plainly which assumption the answer is most sensitive to, and what happens if the end occupier is automated rather than manual, reads as the work of someone who has done this before.

And be honest about uncertainty. Employment forecasting for a building with no named occupier is a structured estimate, not a measurement, and saying so does not weaken the case. It protects it.

This is general guidance, not legal advice; check the position with your local planning authority or a qualified professional before relying on it. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.