Kwiziq's method challenges students to do lots of small kwizzes and is scientifically proven to work!
In May 2011, research conducted by McDaniel et al  investigated the effects of quiz frequency and placement which showed that students who took regular low-stakes quizzes performed up to an incredible 25% better in exams than those who didn't.
Just six months later, the same group published more research, this time investigating whether these effects were enduring. Here's what they concluded: "Once again, we found that quizzing of material produced a positive effect on chapter and semester exams. These results show the robustness of retrieval practice via testing as a learning mechanism... Our results add to a growing body of evidence that retrieval practice in the classroom can boost academic performance." In other words, the benefits of testing regularly are long-term: they last.
Since then a multitude of publications have cited and backed up this research.
1 McDaniel, Mark A et al. "Test-enhanced learning in a middle school science classroom: The effects of quiz frequency and placement." Journal of Educational Psychology 103.2 (2011): 399.
2 Roediger III, Henry L.; Agarwal, Pooja K.; McDaniel, Mark A.; McDermott, Kathleen B. "Test-enhanced learning in the classroom: Long-term improvements from quizzing." Journal of Experimental Psychology: Applied Vol 17(4), Dec 2011, 382-395.