EEF-commissioned FFT to analyse 300,000 students in 250 schools over 9 years and the report, published in June 2020, showed on average, students who spent 10 or more hours on SAM Learning improved 1 GCSE grade better in 2 different subjects. Two grades better means a Progress 8 improvement of +0.2. That could make the difference between Good and Outstanding. 

And disadvantaged students did even better, improving by 1 GCSE grade in 3 and a half subjects.