Writing Case Studies and Past Performance Evidence for Tenders

Ask any seasoned bid writer where evaluators quietly dock marks, and you will hear the same answer: weak past-performance evidence. The supplier can clearly do the work — they have done it ten times — but the case study reads like a brochure, makes vague claims, and never quite proves the point the buyer is being asked to score. The result is a respectable bid that lands just below the winner.

The good news is that this is one of the most fixable parts of a tender. A well-built library of case studies, written to a tight structure and mapped to award criteria, lets you respond faster and score higher on almost every bid you submit. This guide shows you how to build that library and use it well.

Why past performance carries so much weight

Public buyers are spending taxpayers' money and have to justify their choice. Evidence that you have delivered similar work, on time and to budget, lowers their perceived risk — and risk reduction is the real currency of procurement. Many tenders ask explicitly for two or three relevant examples, and quality questions often reward answers that are backed by concrete proof rather than assertion.

The point is not to list everything you have ever done. It is to choose the right examples and tell each one in a way that maps directly onto what the buyer says they value.

Build a reusable case study library

Stop writing case studies from scratch under deadline pressure. Build a small, living library you can draw from. For each significant project, capture a one-page record while the detail is still fresh:

• Client and sector — and whether it was public or private.
• Contract value and duration, so you can match scale.
• The problem the client faced.
• What you did, with specifics.
• Measurable results — figures, percentages, timescales.
• A reference contact and permission to use them.
• Themes it evidences — quality, social value, sustainability, mobilisation, and so on.

Six to ten of these, kept up to date, will cover the vast majority of questions you face. Refresh them quarterly so the figures stay current and contacts do not go stale.

Structure each example with situation, action, result

The structure that consistently scores is situation, action, result — a close cousin of the STAR method. Set the scene briefly, explain what you did (not your sector in general), and finish with the outcome in numbers.

The most common failure is spending three sentences on the situation, one on the action, and none on the result. Flip that balance. Evaluators are scoring what you did and what changed because of it.

As a rough split, aim for roughly a fifth of your word count on the situation, half on the actions you personally took, and the rest on results and lessons. If the question allows it, a short closing line on how you would apply the same approach to the buyer's own contract turns a backward-looking example into forward-looking reassurance.

A case study that ends with a number beats one that ends with an adjective. "Reduced missed collections by 31% within three months" scores; "delivered an excellent service" does not.

Align every case study to the award criteria

This is where most marks are won or lost. Before you choose your examples, read the award criteria and weightings carefully — and if the question set is dense, run it through our free tender summary tool to surface the must-haves quickly. Understanding the scoring scheme tells you exactly what each answer needs to demonstrate.

Then pick the example that proves that specific thing. If a question is weighted heavily on social value, lead with the project where you employed local apprentices, not the one with the biggest contract value. Tailoring beats reusing a generic favourite every time. Mirror the buyer's own language — if they say "mobilisation", use "mobilisation", not "setting up".

A simple trick is to build a quick mapping table in your notes before you write: list each scored question down one side, and against it the case study and the single strongest result you will lead with. Doing this first stops you defaulting to your favourite project and exposes any criterion you have no good evidence for — which is far better discovered now than after submission.

Make your evidence credible

Evaluators are sceptical by training, so make claims easy to believe:

• Use real, specific numbers rather than round ones. "19 days" reads as truer than "about three weeks".
• Name the method. If you cut costs, say how you measured it.
• Offer a reference. A named, contactable client is worth more than a glowing unattributed quote.
• Show relevance. Match sector, scale and complexity to the contract on the table; a £2m example for a £40k contract can read as a poor fit.
• Stay honest. Buyers can and do check, and an inflated claim can sink an otherwise strong bid.

Weave case studies into the wider response

Past performance is not a standalone section to bolt on at the end. The strongest bids thread evidence through the whole document, so each method statement is anchored by a real example. If you are still finding your feet with the format, our guide to writing a tender response shows how the pieces fit together, and the broader path of winning your first government contract puts evidence in context.

Where a tender asks about social value specifically, your case studies should prove delivered outcomes, not promises — our piece on social value in tenders covers what evaluators actually look for.

Common mistakes to avoid

• Reusing the same example everywhere regardless of what the question asks.
• Describing the sector rather than your own actions. "The council needed..." is background; "we did..." is the answer.
• No measurable results. If you cannot quantify it, find a project you can.
• Exceeding the word or example count the buyer specified — evaluators may simply stop reading.
• Stale references who no longer work there or were never asked for permission.

Frequently asked questions

How many case studies should I prepare?

Aim for a working library of six to ten strong, varied examples covering your main service lines and the themes buyers care about, such as quality, social value and mobilisation. Most tenders ask for two or three, so a library of that size lets you pick the best fit each time rather than writing fresh.

What if I have no public-sector experience yet?

Use relevant private-sector or community work and emphasise transferable outcomes, scale and complexity. Be upfront, focus on results, and consider building public-sector experience through sub-contracting or smaller contracts first to create the evidence you will need later.

How recent do my examples need to be?

Tenders often set a window — commonly the last three to five years — so check the question. Within that window, more recent and more relevant examples carry more weight than older or larger but less applicable ones.

Strong evidence only helps once you are bidding for the right contracts, so keep the pipeline full. You can search live UK public-sector tenders on Tendarix and start matching your best case studies to the opportunities that genuinely suit your business.