RFPs provide detailed specifications of what the customer wants to buy and sometimes include directions for preparing the proposal, as well as evaluation criteria the customer will use to evaluate offers. Customers issue RFPs when their needs cannot be met with generally available products or services. RFIs are issues to qualify the vendors who are interested in providing service/products for specific requirements. Based on the response to RFI, detailed RFP is issued to qualified vendors who the organization believes can provide desired services. Proposals in response to RFPs are seldom less than 10 pages and sometimes reach 1,000's of pages, without cost data.
Request for Quotation (RFQ)
Customers issue RFQs when they want to buy large amounts of a commodity and price is not the only issue--for example, when availability or delivering or service are considerations. RFQs can be very detailed, so proposals written to RFQs can be lengthy but generally much shorter than an RFP-proposal. RFQ proposals consist primarily of cost data, with small narratives addressing customer issues, such as quality control.
Invitation for Bid (IFB)
Customers issue IFBs when they are buying some service, such as construction. The requirements are detailed, but the primary consideration is price. For example, a customer provides architectural blueprints for contractors to bid on. These proposals can be lengthy but most of the length comes from cost-estimating data and detailed schedules.
Request for Information (RFI)
Sometimes before a customer issues an RFP or RFQ or IFB, the customer will issue a Request for Information (RFI). The purpose of the RFI is to gain "marketing intelligence" about what products, services, and vendors are available. RFIs are used to shape final RFPs, RFQs, and IFBs, so potential vendors take great care in responding to these requests, hoping to shape the eventual formal solicitation toward their...