PQQ vs SQ vs ITT: What Is the Difference and How to Prepare for Each

If you are new to public sector tendering, the alphabet soup of procurement terminology can be confusing. PQQ, SQ, ITT, RFP, RFQ, and other abbreviations each refer to specific stages and documents in the procurement process. Understanding the differences is essential for preparing the right type of response at each stage.

This guide explains the three most common stages in plain terms and covers what you need to prepare for each.

The Two Stage Procurement Model

Most public sector procurement in the UK uses a two stage process. The first stage filters suppliers based on organisational capability. The second stage evaluates specific proposals from shortlisted suppliers.

Think of it as a gateway. Stage one checks whether you are qualified to bid. Stage two assesses whether your specific offer is the best.

What Is a PQQ?

A Pre Qualification Questionnaire (PQQ) was the standard name for the first stage filter under the old EU procurement regulations. Since the introduction of the standardised Selection Questionnaire, the term PQQ is technically outdated for UK central government procurement. However, many buyers, especially in the private sector and some local authorities, still use the term PQQ informally.

PQQs assess your organisational standing rather than your specific proposal. They cover company information and legal status, financial standing including turnover, insurance levels, and credit references, health and safety management, environmental policies, equal opportunities and modern slavery compliance, quality management systems and accreditations, and relevant experience through case studies.

The purpose is to ensure that only suppliers who meet minimum capability thresholds progress to the tender stage. Failing a PQQ means you are excluded from the opportunity entirely.

What Is an SQ?

The Selection Questionnaire (SQ) replaced the PQQ for above threshold public sector procurement under UK regulations. In practice, the SQ covers the same ground as a PQQ but follows a standardised format published by the Crown Commercial Service.

The SQ is divided into three parts. Part 1 covers supplier information. Part 2 covers exclusion grounds, asking whether your organisation has any mandatory or discretionary exclusions such as fraud, corruption, or tax offences. Part 3 covers selection criteria, assessing your technical and professional ability, financial standing, and relevant experience.

For practical purposes, if you see "SQ" or "PQQ" on a procurement notice, the preparation is the same. You need your organisational evidence, case studies, and compliance documentation in order.

TenderVera provides dedicated PQQ and Selection Questionnaire support for suppliers who need help structuring these submissions.

What Is an ITT?

An Invitation to Tender (ITT) is the main tender document, typically issued after the PQQ or SQ stage (or directly in an open procedure). This is where you submit your detailed proposal, including quality responses, method statements, pricing, social value commitments, and any other requirements specified by the buyer.

The ITT is where contracts are won and lost. While the SQ stage filters on organisational capability, the ITT stage evaluates your specific approach to delivering this particular contract.

ITT responses typically need to cover methodology and approach (how you will deliver the contract), resource plan (who will deliver it and with what equipment), quality assurance (how you will maintain standards), risk management (how you will handle challenges), social value (what community benefits you will deliver), pricing (your commercial offer), and mobilisation (how you will transition into the contract).

Each quality question is scored against published evaluation criteria, and scores are combined with your price to determine the overall winner.

Key Differences at a Glance

The SQ or PQQ assesses whether your organisation is suitable. The ITT assesses whether your specific proposal is the best. SQ responses draw on standing evidence such as policies, accreditations, financial statements, and case studies. ITT responses require bespoke content tailored to the specific contract, buyer, and evaluation criteria.

Failing an SQ means exclusion. Scoring poorly on an ITT means losing to a better response.

How to Prepare for Each Stage

SQ and PQQ Preparation

Build a library of standing documentation that you keep current. This should include current insurance certificates (employers liability, public liability, professional indemnity), recent audited or management accounts, health and safety policy and risk assessments, environmental policy, quality management documentation or ISO certifications, equal opportunities and diversity policy, modern slavery statement, three to five recent case studies in your key sectors, and GDPR and data protection documentation.

Keep this library updated quarterly so you can respond to SQ requirements quickly without scrambling for documents each time.

ITT Preparation

ITT preparation is contract specific. For each opportunity, read every document in the tender pack before writing anything. Create a compliance matrix mapping every requirement to your response. Identify the evidence and case studies most relevant to this specific contract. Brief your delivery team to provide technical input on methodology. Allocate time based on question weightings, giving more attention to higher value questions. Build in review time before the deadline.

For guidance on structuring your ITT responses, read our guide on writing compelling tender responses.

Common Mistakes at Each Stage

SQ and PQQ Mistakes

Using outdated certificates or financial statements. Providing generic case studies that do not demonstrate relevance to the opportunity. Missing mandatory exclusion declarations. Exceeding word or page limits on policy summaries.

ITT Mistakes

Submitting generic responses that could apply to any contract. Ignoring the evaluation criteria when structuring your answer. Providing vague methodology without specific commitments. Leaving social value sections until the last minute. Failing to use the full available word count.

When to Get Professional Support

If you consistently pass the SQ stage but lose at ITT, your organisational evidence is strong but your proposal writing needs work. Professional bid writing services can help you structure ITT responses that score well.

If you are failing at SQ stage, the issue is usually presentation rather than capability. Your case studies may not highlight the right evidence, or your policies may not address the specific requirements. PQQ and SQ support can help you restructure your evidence.

Conclusion

Understanding the difference between PQQ, SQ, and ITT stages is fundamental to effective tendering. Each stage requires different evidence and a different approach. Prepare your standing documentation in advance for SQ and PQQ submissions, and invest the time to tailor each ITT response specifically to the contract and buyer.

The suppliers who win consistently are the ones who treat each stage with the preparation it deserves.