In case your missed this must read:
Privately funded exit poll in 3 CA Counties showed a reported Sanders Win by 3.1% was really a Sanders Win by 7.5%
ADEI conducted exit polls during the 2016 California presidential primary in three counties at 12 precincts….. The polls were randomized and representative of the demographic data in the precinct area. The counties were Contra Costa, Santa Clara, and Alameda Counties and four polling places were chosen in each county. The sample size was 3, 321. This is an impressive number of people,by the way, as Edison Research Media will often poll only 1200 people in a national presidential election. Lori Grace of the Institute managed the followup which included a week of filing the 3,321 exit poll results into an Excel spread sheet. After that Tina Kimmel PhD, MPH, MSW and Josh Mittel PhD analyzed the data. Both people have an extensive background in statistics.
With respect to the Democratic primary, the results were the following: The official vote for these three counties show Sanders winning over Clinton 49.2% to 46.1%, a 3.1% margin. By official, I mean what was reported at the Secretary of State’s office. The exit polls conducted by the Institute showed Sanders winning over Clinton in a unadjusted exit poll 52.6% to Clinton’s 43.8%. Then we adjusted the results for demographic data and the difference became 51.9% for Sanders and Clinton 44.4%-still a fairly large Sanders victory of 7.5% . You might ask what kind of demographic data did we adjust for. The exit pollers found that older white men did not often agree to fill out the exit poll. They tended to be Trump, Johnson and occasionally Clinton supporters. Gary Johnson is the Libertarian candidate. So for the people who did not participate in the exit poll, many of which were older white men, we added some votes for Trump, Johnson and Clinton proportionally to the exit poll results that we already had.
The Institute used the Senate race as a “benchmark” against the presidential race. This is done in all good polling where you pair a vote you are interested in, like the presidential candidate with the senatorial candidate. The ADEI exit poll results for both candidates Kamala Harris and Loretta Sanchez matched the official voting tally within the 2 percent margin of error. A 2 percent difference in the margin of error is common in most exit polls and is not considered a fraction of election irregularities or fraud.