Development of a concept inventory for strength of materials

With the success of David Hestenes´s force concept inventory, many educators are now working on developing concept inventories for other subjects such as math, biology and engineering science. Development of a useful concept inventory is not easy, however. This paper describes development of two concept inventories for strength of materials, the first of which was a failure. Psychometric testing of this concept inventory indicated serious deficiencies. A new and larger project team was assembled (including the second author) to develop a better inventory. The results of the psychometric analysis of the first inventory, which showed its shortcomings, are first presented, followed by the improved development procedure for the second inventory. Finally, the lessons learned developing first a failed inventory and then a promising inventory are discussed.