Works managed by ISD fall into 3 categories:
Order of cost
The order of cost estimate is an indication of the likely cost of a project based on information available at the initial proposal.
Indicative cost estimate
Also called a 'ball-park estimate', an indicative cost estimate has a ±30% order of accuracy. Developed at the project identification and assessment stage, it is used to determine if funds are likely to be available and whether to proceed with the proposal.
Brief stage cost
The briefing stage cost estimate is prepared using the project brief developed for the selection of the principal consultant for the project. It is based on known building costs from similar projects, with external costs indicated separately.
Budget estimate or outline proposal cost
This is the estimated cost of the project and has a ±20% order of accuracy. It is based on the results of the project feasibility study, including a more detailed scope of the works required and delivery option plans. The budget estimate is used to determine whether the project should proceed, and if and how it could be funded.
Estimate or sketch design cost
The estimate or sketch design cost estimate has a ±10% order of accuracy and is produced during the design development or schematic design phase of the project. The estimate is based on drawings of project delivery options, which are then assessed to determine which option will be pursued.
Tender estimate or tender document cost plan
The tender estimate or tender document cost plan estimate is based on the documentation prepared for distribution to businesses wishing to submit tenders for delivery of the project.
The tender price is the price received from tenderers for a capital works project. It is the cost that the market has determined is applicable to the project at the time tenders were called. The tender price is based on detailed plans, drawings and specifications.
A quote or quotation is cost estimate provided by a contractor for a small project. It is based on a limited scope of works and specifications.