AbstractThe emphasis given to experimental problem‐solving skills in science curriculum innovation has not been matched by the development of comparable assessment tools. Multiple‐choice tests were constructed for seven skills using learning hierarchies based on expert‐novice differences. The instruments were refined in three phases of field testing. The reliabilities of the tests are sufficient for making judgments of group performance, but are insufficient in a single administration for individual assessment. Evidence of the validity of the tests is presented and their worth is discussed within the framework of a theory of instru