Over the past four years problem solving ability tests have been administered to a national sample of primary age students. The data has been examined using factor analysis, and combinations of single and multi-dimensional and multi-component item response modelling. Results suggested that the problem structure should be altered from what was essentially a multi step mathematics problem to one that emphasised thinking strategies. Teachers were advised of the strategies that led to successful resolution and from these discussions, intervention strategies were identified. These were then implemented in the classroom to examine their effectiveness in improving students' problem solving strategies and resolution.