- Pollsters often use party allegiance to sanity check their results, but that's irrelevant in a primary
- No one really pays attention to a primary early on (unlike presidential campaigns, which start earlier and earlier every cycle), so early polling is not representative of final voting
- Pollsters have to guesstimate how many voters of a certain type will show up at the polls, but nonpresidential primaries are super low turnout historically especially in noncompetitive areas, and some disgruntled voters for insurgent campaigns can upset this prediction
- Pollsters have a hard time reaching young people and minorities, who are usually not on landlines and are less likely pick up numbers from strangers
TLDR:
- Pollsters often use party allegiance to sanity check their results, but that's irrelevant in a primary
- No one really pays attention to a primary early on (unlike presidential campaigns, which start earlier and earlier every cycle), so early polling is not representative of final voting
- Pollsters have to guesstimate how many voters of a certain type will show up at the polls, but nonpresidential primaries are super low turnout historically especially in noncompetitive areas, and some disgruntled voters for insurgent campaigns can upset this prediction
- Pollsters have a hard time reaching young people and minorities, who are usually not on landlines and are less likely pick up numbers from strangers