The problem based approach, referred to as scientific, mainly involves convergent thinking which seek to identify patterns and from those the BEST way to solve a given problem. The solution based approach, depending of the performers level of creativity, mainly involves divergent thinking and is referred to as architectural. It seek new work processes and rather than the best solution, it focus on finding A solution.
By mixing the two approaches, architectural design can during its ideation and design phases evolve dramatically from a very simple proposal to something that seem simple, but hold a high level of complexity. This result depends on how well the performer is aware of his or her work processes.