Methods note · version 0.2 · 24 September 2026
Study boundaries
Feng, Patton and Davis (2017) link fixed outputs from previously conducted EXODIS simulations to a UK agricultural partial equilibrium model. We transcribe its Tables 1, 3 and 4. The dashboard neither generates disease paths nor evaluates operational actions. The source model's 2017 projections and whole-UK export closure assumptions are historically situated and cannot be interpreted as a 2026 forecast.
Source and comparability register
| Source | Measure and price year | Coverage | Comparability |
|---|
| Feng et al. 2017, Tables 1, 3, 4 | Modelled 2017 prices, production, gross output; 2017–25 discounted output | UK beef, sheep, pigs | One internally comparable model family; trade adjustment alternatives are sensitivities |
| NAO 2002 | >£3bn public; >£5bn private, 2001-era pounds | Observed 2001 event and wider economy | Historic scale only; no equivalence to the 2017 market scenarios |
| NAO 2025 | £5.2bn public; £8.6bn private, 2023–24 pounds | Re-expressed 2001 event | Do not add to NAO 2002 |
| Barnes et al. 2023 | Survey-based uncompensated farm costs; no FMD estimates | 1,600 dairy and beef holdings in England and Wales, bTB | Transfer cost taxonomy and survey method only |
| Syntera FMD / LP / PE / ASF | Prototype parameters and code; mixed or undated price basis | Various, not a common calibrated baseline | Architecture and illustrative farm sensitivity only |
Calculations and uncertainty
For a selected published row, the dashboard computes gross output difference = published scenario value − published baseline value and price change = (published scenario price / published baseline price − 1) × 100. The price shown is rounded to one decimal place. The long-run approximation is published baseline × published rounded percentage. Its rounding error is at most about 0.05 percentage points of baseline per row. No unreported confidence interval is invented; selected 5th, median and 95th outcomes belong to the source simulation, while import-displacement columns are structural sensitivities.
For the farm illustration, baseline gross margin = prototype animals × prototype margin per head; price-exposed revenue proxy = animals × assumed output per head × published price change is unavailable because the prototype does not supply consistent product output per head. The interface therefore displays baseline gross margin and the published commodity price movement side by side, without converting it into a farm-income loss. A change in income over time requires farm production schedules, variable costs, compensation and actual restriction records.
Model code review
- LP: farm resilience optimiser uses monthly sheep/cattle feed, labour and forage constraints with SciPy linear programming. Its source audit labels disease shock and sector scaling assumptions low confidence; it has no validated pig enterprise in that page. Do not present a solved LP result without a shared farm dataset.
- DP: the FMD twin contains a
dp_bridge of fixed proxy thresholds and actions. It is not a fitted value function or a validated economic dynamic programme. No DP result is imported. - PE: UK FMD engine reads commodity production and trade files and scenario configuration. Its baseline, currency conversion, trade classifications and elasticity calibration need a verified common year before welfare integration. The peer-reviewed Feng paper's modelled price and output results are used directly instead.
- Pig / ASF: ASF GB configuration explicitly labels per-head costs, diversion and closure assumptions illustrative and undated. The reusable insight is a provenance register and separate trade channel; ASF-specific coefficients are not transferred as FMD estimates.
Cost ledger and overlap
| Item | Interpretation | Overlap rule |
|---|
| Gross output value change | Price × quantity across modelled livestock production | Already captures price and production; never add lost export sales or farm turnover directly |
| Farm gross margin | Output less variable costs in a farm enterprise | Farm subset of sector output; do not add to sector value change |
| Trade at risk | Gross blocked export revenue before diversion or import adjustment | Market price response already includes trade shock |
| Public spending | Response operations plus possible compensation | Compensation is a transfer; resource use requires line items |
| Producer / consumer surplus | Area under calibrated supply / demand schedules | Requires integrated equilibrium; no sum with output or spending without reconciliation |
Barnes et al. farm costing method
Barnes, Moxey, Brockelhurst, Barratt, McKendrick, Innocent and Vosough Ahmadi (2023) survey 1,600 dairy and beef holdings in England and Wales to measure farmers’ consequential, uncompensated bTB breakdown costs. Testing, movement restrictions and lost output together account for more than three quarters of these costs; estimates are skewed and vary with herd size and duration. An FMD study can adopt its bottom-up survey logic, separate compensated animal values from uncompensated business costs, and stratify farms by type and duration. Its bTB monetary estimates must not be transported to FMD.
Limitations and next research steps
The 2017 market study assumes UK-wide export closure and 90 days after the last case for the two strategies it compares; it does not cover milk market results, contemporary trade agreements, 2026 prices, public response budgets or welfare accounting. Its policy comparison is conditional on its fixed inputs and import adjustment. A publishable integrated study requires access to consistent farm budgets, current UK/GB trade values, calibrated PE elasticities, fiscal line items and matched source simulation outputs. It must document regionalisation, Northern Ireland coverage, discounting and double counting before reporting total social welfare.
References
- Feng, S., Patton, M. & Davis, J. (2017). Market Impact of Foot-and-Mouth Disease Control Strategies: A UK Case Study. Frontiers in Veterinary Science 4:129.
- National Audit Office (2002). The 2001 Outbreak of Foot and Mouth Disease.
- National Audit Office (2025). Resilience to animal diseases.
- Barnes, A.P. et al. (2023). The consequential costs of bovine tuberculosis breakdowns in England and Wales. Preventive Veterinary Medicine 211, 105808.
- Defra (2026). Agriculture in the United Kingdom 2025, Chapter 8: Livestock.