A program for national educational evaluation was established in Sweden in 1989. In 1992, a second data collection was carried out. The program is designed to serve national and local purposes of evaluation. One concept that has been emphasized strongly is an "explorative way of working." Evaluating an explorative way of working is a complex problem that has been addressed through a problem-solving task. A test of this approach was conducted in 1992 with 51 classes of ninth graders divided into 239 groups of 4 to 5 students. Students were asked to solve a problem involving acidification and their problem solving approaches and results were studied. Half the groups kept to the problem but the other half expanded their focus, showing a lack of stringency and concentration. Forty percent of the groups did not make any penetrating study to answer any of the posed questions. Twenty-five percent of the groups followed their own plans and treated only the questions they planned to address. Students showed little independence in relation to their information sources, and barely half of the groups carried out an investigation. When they were made, investigations were usually well prepared with regard to the form of the report, but they were usually not adequate with regard to content. Half of the groups organized their work well, and teachers thought the working atmosphere was favorable in 80% of the groups. Overall, results show that students have not reached the goals set up by the planners for an explorative and critical way of working. Implications for the improvement of teaching and learning are discussed. (Contains one figure and four references.) (SLD)