From the conclusion of study of the Democratic Party primary elections this year by Rodolfo Cortes Barragan, Stanford University, and Axel Geijsel, Tilurg University, The Netherlands, entitled: "Are we witnessing a dishonest election? A between state comparison based on the used voting procedures of the 2016 Democratic Party Primary for the Presidency of the United States of America," dated June 7, 2016:

Are we witnessing a dishonest election? Our first analysis showed that states wherein the voting outcomes are difficult to verify show far greater support for Secretary Clinton. Second, our examination of exit polling suggested large differences between the respondents that took the exit polls and the claimed voters in the final tally. Beyond these points, these irregular patterns of results did not exist in 2008. As such, as a whole, these data suggest that election fraud is occurring in the 2016 Democratic Party Presidential Primary election. This fraud has overwhelmingly benefited Secretary Clinton at the expense of Senator Sanders.

Essentially, Barragan and Geijsel looked at states where there was no paper voting trail (i.e., e-voting machines) and found Clinton did significantly better in those states than Sanders compared to states where a paper trail existed. They also showed that exit poll results deviated significantly from final results by a large margin in Clinton's favor. Further, discrepancies between the exit polls and final results were wider in states where there was no paper voting trail.

The authors used the 2008 primary elections as a control for this year's primaries. They found that in the 2008 primaries between Clinton and Obama there were no such voting anomalies between states with paper voting trails and and states without paper voting trails. If you're a statistician, please feel free to examine their paper at greater length.

Here's a pie chart graphic from the study that shows the differences in a way anyone can understand:

Make of this what you will.