Benchmark methodology

1. Data collection

All price data on SupplyIndex originates from real supplier invoices submitted by independent UK practices. We do not scrape supplier websites, accept price list submissions from suppliers, or use list prices as data points.

The supplier directory spans every sector — dental, optical, veterinary, pharmacy, aesthetics, audiology and allied health. Benchmarks are live first for aesthetics and dental, and open in each other sector as members contribute invoices. Cross-sector overheads (card processing, energy, telephony, insurance and more) are available to every practice from day one.

Practices submit data via four methods:

📄

Invoice upload

Upload a PDF or invoice image. We extract supplier, product, quantity and net price using AI vision, with manual review.

📧

Email forward

Forward supplier invoice emails straight to your unique SupplyIndex address — nothing to download or re-upload. We extract and anonymise them automatically.

⌨️

Manual entry

Enter price data via a structured form with supplier, product name, quantity and net price fields.

🔗

Accounting integration

Coming soon: direct integrations with Xero and QuickBooks for automated invoice extraction.

2. Validation pipeline

Every invoice runs through a series of automated checks, and only confirmed line items ever feed a benchmark.

Check 1

Supplier & authenticity

We match the extracted supplier against our known-supplier list, validate any VAT number, and require the invoice to be dated within 3 months of upload — so benchmarks reflect current prices.

Check 2

Product matching

Each line item is matched to a canonical product in our catalogue (exact, fuzzy and manual). Items that cannot be confidently matched are held out of benchmarks.

Check 3

Duplicate detection

We flag likely duplicates — the same practice submitting the same invoice date with a near-identical total — so a single invoice cannot be counted twice.

Check 4

Review & confirmation

Only confirmed line items feed benchmarks. Extractions that pass our checks with high confidence confirm automatically; anything that does not is manually reviewed before it can contribute.

3. Benchmark calculation

Benchmarks are recomputed every day from all confirmed invoice data. For each product with enough data we report:

Statistic	Description
P25	25th percentile — the lower quartile, a realistic "good deal" benchmark
P50 (Median)	The middle value — half of practices pay more, half pay less
P75	75th percentile — the upper quartile; above this suggests overpaying
Sample size	Number of data points and distinct practices in the calculation

Minimum data threshold: We require a minimum of 20 data points from at least 5 distinct practices before publishing a benchmark for a product. Below this threshold, products show a “Benchmark pending” status. This prevents small datasets from producing misleading benchmarks.

4. Freshness and trends

Benchmarks are recomputed every day, so they always reflect the latest confirmed invoices. All confirmed prices in the current dataset count equally — we do not hand-weight or adjust individual figures.

We keep a monthly history for each unlocked product so you can see how a price has moved over time, and we alert members tracking a product when its median moves materially (5% or more) between runs.

5. Anonymisation and privacy

Individual practice prices are never disclosed. All benchmarks are aggregated statistics only. Additionally:

Individual practice prices are never shown — every benchmark is an aggregate across at least 5 distinct practices
A benchmark is only published once it clears the minimum threshold (20 data points from at least 5 practices); below that it shows as “benchmark pending”
NHS pricing is held separately and excluded from private benchmarks by default
You can request deletion of your contributed data at any time

6. Limitations

We are committed to honest communication about what our benchmarks can and cannot tell you:

⚠Benchmarks reflect prices paid by practices in our network, which may not be perfectly representative of all UK practices.

⚠Volume discounts, loyalty agreements, and buying group memberships mean that the correct benchmark for your practice may differ from the overall population median.

⚠Product specifications can vary (e.g. pack size, unit count, or whether accessories or consumables are included). We standardise where possible, but users should verify unit comparability.

⚠Benchmarks are informational only and do not constitute commercial advice. Always negotiate directly with your supplier.

Questions about our methodology?

We welcome scrutiny of our approach. If you spot an error or have a methodological concern, please get in touch.

Benchmark Methodology