From the TNT this morning:

A random test shows 85 percent of the Pierce County primary election ballots are being marked properly and will be counted for partisan races, Auditor Pat McCarthy said Tuesday.

The checks of 200 randomly selected ballots – made Monday at the request of state elections officials – showed 169 voters indicated a party choice by connecting the front and back of an arrow with a line.

Conversely, 31 voters, or 15 percent, did not choose a party. As a result, their choices in partisan races can’t be counted under state law. Of the 31 ballots that did not indicate a party choice, 19 were marked along straight party lines, 11 were marked for only nonpartisan races and issues, and one was left blank.

Why is 20 percent in Snohomish County bad, but 15 percent in Pierce ok?