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 contractbetween 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

- A call off or a term contract is one which exists for a fixed period of time, rather than for a specific purpose
- A formal framework agreement does have some legal standing but it is not a contract, primarily because there is no consideration involved, but it is an overarching (or umbrella) agreementunder which contracts can be created (this holds true in English law but may not be right in other jurisdiction)
- A framework arrangement is a rather loose set-up, without any legal standing. It usually occurs when an organisation has decided for itself to limit the number of suppliers it is willing to work with and, through a purely internal process, sets up an approved list of such suppliers.
- A performance management framework including KPIs and targets, the assessment scheme and incentives, disincentives, bonuses and penalties. It is a schedule to a contract and only legally binding if it is referred from contract clauses.
Reference: CIPS study guide page 59-63
LO 1, AC 1.3

Variable pricing is suitable to situations when the cost of certain elements of the product fluctuate unpredictably. For road building, asphalt fluctuates regularly. Furthermore, 5 years are long period, then variable pricing is the most appropriate method to achieve value for money and control budget.
A contract for window cleaning during the next three months is a short-term service contract, fixed price is the most suitable method.
A contract for the supply of lubricating oil for immediate delivery is an one-off contract, only fixed price is applicable.
A contract for the supply of 100 printing machines to be delivered next month is also an one-off contract.
Reference: CIPS study guide page 172-183
LO 3, AC 3.3

A guarantee is an agreement given by a trader to a consumer, without any extra charge, to repair, replace or refund goods that do not meet the specifications set out in the guarantee. A guarantee is usually issued by the manufacturer of goods or by a trader that provides goods as part of a service - replacement windows, for instance. Generally, a guarantee provider undertakes to carry out free repairs, for a set period of time, for problems that can be attributed to manufacturing defects.
Reference:
- Guarantees and warranties
- CIPS study guide page 157-159
LO 3, AC 3.2

Specifying that suppliers hold certification to standards like ISO 14001 offers assurance that they adhere to recognised environmental management practices, promoting consistency and reliability. Such standards are internationally recognised, facilitating understanding among both local and global bidders. However, certification does not guarantee the exclusion of all polluting suppliers, nor does it eliminate the need for internal environmental training within the purchasing organisation.
Reference:CIPS L4M3 Commercial Contracting Study Guide, Chapter 2, Section 2.1.1 - Benefits and risks of market dialogue with suppliers.