An invitation to treat is an action inviting other parties to make an offer to form a contract. These actions may sometimes appear to be offers themselves, and the difference can sometimes be difficult to determine. The distinction is important because accepting an offer creates a binding contract while "accepting" an invitation to treat is actually making an offer.
One simple test to distinguish an offer and an invitation to treat is to ask what this statement will become when it is accepted. Now we apply this test to four options:
- Tender bid: Tender bid is submitted by a supplier to an invitation to tender from the buyer. It states the specific quantity, price and other elements. If buyer accepts the bid, there will be a contract between them. Therefore, a tender bid is an offer.
- Purchase order: Purchase order which is sent by a buyer will state the items, the quantity, the price and terms and conditions. If supplier accepts the purchase order, there will also be a contract between two parties. It is also an offer.
- Price list: Price list is prepared by a supplier. The price list often states the items and unit price. If a buyer accepts it, the contract has not yet been formed since the contract scope has not yet been decided. It is an invitation to treat.
- Invoice: Invoice is often sent after a contract is formed. It is in fact a request for payment, neither offer nor invitation to treat.
Reference:
- CIPS study guide page 29-32
- What Is an Invitation to Treat?
LO 1, AC 1.1

Construction procurement is particularly complex and risky. Forming a contract in construction may take lots of time and energy of both client and contractor. Therefore, standardisation in construction contract would help the buying organisation to save their precious resources. Furthermore, the wording of these model form contracts is accurate as it has been agreed among the professionals within an industry.
One of the advantage of using model forms of contract is the balanced of risk and reward allocation between the contractor, consultant engineer and the client.
Reference:
- An Introduction to FIDIC model contracts
- CIPS study guide page 139-147
LO 3, AC 3.1

An implied term is a term which the courts imply into a contract because it has not been expressly included by the parties. This may be because the parties did not consider it, did not think that any problem would arise in relation to it or simply omitted to include it.
The courts are very reluctant to imply terms into contracts and will only do so in the following circumstances:
- terms implied under statute
- terms implied under common law
- terms implied because of custom or usage
- terms implied due to previous dealings
- terms implied 'in fact' or to reflect the parties' intentions
Reference:
- Contracts: Express and Implied Terms
- CIPS study guide page 32
LO 1, AC 1.2

An offer is a full statement of what the offeror is willing to provide and the terms by which they are willing to provide it.
There are some statements that are not offers:
- Invitation to treat: this states that a person or organisation is willing to enter into discussions about the possibility of a deal, but does not confirm a willingness to be bound by any terms mentioned. Catalogues, goods on display and ITTs are invitation to treat.
Civil law countries may have different perspective on this matter. Article 2:201 (3) of The Principles of European Contract Law states: 'A proposal to supply goods or services at stated prices made by a professional supplier in a public advertisement or a catalogue, or by a display of goods, is presumed to be an offer to sell or supply at that price until the stock of goods, or the supplier's capacity to supply the service, is exhausted.' Learners are advised to look at their countries' legislation for more information on offer and acceptance.
- Declaration of intention: this is defined as an aim or a plan.
- A 'mere puff' (or boast): this is anything which is not intended to be taken literally or seriously, such as many advertisement.
- Provision of information: merely provides information, but provider does not confirm willingness to be bound.
Reference:
LO 1, AC 1.2

Standards are incorporated into specifications by simply cross-refering to the relevant standard by its number and date of publication. It is important to include the date of publication. All standards are reviewed from time to time and their content changes. The absence of the publication date will lead to disrupts over which version of the standard actually applies to the contract.
Reference:
LO 2, AC 2.1