Washington Primary was also an open primary just as the caucus.

They apparently don't have party affiliation on their voter registration. They just need to declare that they consider themselves to be a Democrat. It appears that after 60 days it will be unknown which primary they were a participant. Also, voters could vote in both the caucus and primary as long as the political party is the same for both.

If Washington was included as an open primary regarding how many each candidate has won it would be Clinton: 10 -- Sanders: 4.

So even though independents could vote their Democratic Primary Clinton still did well in Washington.

Washington is one of only a few states that had a higher voter turnout than in 2008. In 2008, Washington also had both a caucus and primary with the caucus being used to determine allocation of delegates.

Because their caucus is the determining event Washington can only use the Cluster bonus which allocates an additional 15% bonus delegates. 9 at the district level and 3 at the at-large level. If they used the primary as their determining event they would have a 20% bonus which would give them 11 delegates at the district level and 4 at the at-large level.