What should an invitation to tender pack contain?

A good ITT pack answers, in advance, every question a tenderer would otherwise resolve with a different assumption, because each assumption is a reason the returns come back non-comparable. It needs a scope description precise enough that four tenderers price the same works, with the interfaces and the things that fall between trades named. It needs a pricing schedule structured into the lines you intend to level against, so returns break down comparably rather than as single lump sums. It needs the preliminaries and attendances stated explicitly, who provides access, welfare, plant, scaffold, power and waste, since unstated attendances are the commonest cause of prices that cannot be compared. It needs the tender programme and key dates. And it needs the contract terms the package will be placed under, the payment mechanism, programme obligations and damages regime, because a price given without sight of the terms is one the tenderer will revise the day they read them. An hour closing gaps in the enquiry saves a week reconciling incomparable returns, and designs out the post-tender surprise where the winner reads the terms and asks for more.

Take a small main contractor putting a groundworks package out to four subcontractors as drawings and a one-line request for a price. The returns are unusable: one excludes the muck-away, one assumes the main contractor provides the setting out, one prices a single lump with no breakdown, and one priced a different drawing revision. Levelling takes a fortnight, and the apparent cheapest, once exclusions are added back, turns out the dearest. The next package goes out as a proper pack: a scope note naming the setting out and muck-away as the subcontractor's, a schedule broken into the bill sections, the attendances stated, and the JCT subcontract terms enclosed. Four comparable returns come back, the levelling takes an afternoon, and the order is placed on a number that does not move.