Yes? Maybe? I still have no idea! I think so though!
I analyzed my 5th grade students' end of year NWEA data and compared it with their Khan Academy Energy Points. Students who were in the top 1/3 of the class for Energy Points grew, on average, a whopping 2.5 years during this past school year. Those in the bottom 1/3 for Energy Points still grew, but only 0.7 years. The below graph shows this striking relationship between Khan Academy activity (in terms of Energy Points earned) and student growth.
Please question the methodology and validity of this data as you please. I'm interested in hearing your thoughts and plan on building this post based on the discussion via comments/emails.