This model can refer to any instructional method in which students work together in small groups toward a common goal. As such, collaborative learning can be viewed as encompassing all group-based instructional methods, including cooperative learning . On the contrary, according to  some authors distinguish between collaborative and cooperative learning as having distinct historical developments and different philosophical roots. Nevertheless, regardless of the interpretation, the core element of collaborative learning is the importance of students' interactions rather than on learning as a solitary activity. There is clear consistency among the findings of various studies on the question of how collaboration influences learning outcomes. In a review of 168 studies,  found that cooperation improved learning outcomes relative to individual work across the board. Similar results were found by  who looked at 37 studies of students in science, mathematics, engineering and technology. A question of practical interest is whether the benefits of group work improve with frequency. In a study "investigating the effect of incorporating small, medium and large amounts of group work on achievement",  found the positive effect sizes associated with low, medium and high amount of time in groups to be 0.52, 0.73 and 0.53, respectively. Therefore, the highest benefit was not found for large time in groups but for medium time in groups. In contrast, more time spent in groups did however produce the highest effect on promoting positive students' attitudes, with low, medium and high amount of time in groups having effect sizes of 0.37, 0.26, and 0.77 respectively. The authors also noted that the attitudinal results were based on a relatively small number of studies.