Simply stated, the purpose of inspection is to ensure that the materials and workmanship provided by the contractor comply with the relevant codes, ordinances, plans and specifications. Note that we say materials and workmanship. The best designs and materials are of no value without good workmanship. The complexity of construction today, the emphasis on speed of construction, and the increasing interest in quality control and quality assurance underscore the importance of impartial inspection of the highest degree of competence. One thing should be made clear: the inspector does not supervise the contractor's operations. Keeping this in mind, we can say that, in general, properly applied inspection should aid in ensuring that: the requirements of the contract documents will be carried out, extra work will be minimized, the use of unacceptable substitutes will be avoided, making errors that might result in unnecessary maintenance cost will be avoided, and materials and workmanship that are guaranteed will be evaluated at the time of installation. The American Concrete Institute's "Recommended Practice for Concrete Inspection" lists a number of items normally included in inspection of concrete. These can be summarized as: inspection and approval of batching and mixing plants, truck mixers and transporters; control of the proportioning of concrete mixes and- on some jobs and under some circumstances- the design of mixes; inspection in the batching and mixing plant if size of job or type of concrete warrants it; inspection, testing and approval of materials used in the concrete- involving tests of aggregates as well as inspection of the handling of aggregate, cement and admixtures; inspection of forms and falsework, embedded items, reinforcing steel and other items related to the preliminaries before placing concrete; and preparing reports covering all of these inspections and test.