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The West Coast Effect is the term given to an election controversy that dates back to the 1960’s when the national broadcast started. This controversy centers around early reporting on the east coast and the impact it has on west coast voters. While the commonly studied effect on west coast voter didn’t have an effect on 2016 early voting reports might have a similar effect.


The first research into in the West Cost effect was done in the 1966 election (Fuchs, 1966; Mendelsohn, 1966; Lang & Lang, 1968), and found to be no evidence of the effect of early reporting, but it had a few problems. One of the issues was that all three studies assume that voter made a decision on an election, which is known to only be a few. The voters in the studies only showed that pre-election polls would have caused the west coast voters to stay home, then only hear about a Goldwater upset because that would have changed the results. The other problem was that they ignore the central question of what the effect on the local level. And the biggest one was that the 1966 election was never close to the east coast vote total provided no new information to west coast voters.

In the three Lang & Lang’s book Voting and Nonvoting: Implications of Broadcasting Returns Before Polls Are Closed (1968) was more far-reaching and was considered the definitive study for over a decade. The survey was limited to, Oakland County and the members surveyed (438) resulted in large margin of error, and once the early voter was eliminated there slightly more the 100 making the study inconclusive.

In the 1980’s there was a second wave of research on the West Cost Effect, which included multiple studies. Of the studies, three of the studies (Delli Carpini, 1984; Dubois, 1983; Epstein & Strom, 1981) used aggregate data rather than surveys to overcome the lack of a sufficient data pool, while (Jackson, 1983) used a much larger survey. While Epstein & Strom (1981), Dubois (1983), and Delli Carpini (1984) used to aggregate data, they all chose different details from Epstein and Strom (1981) using regional turnout data (West Coast, Pacific Northwest, Rocky Mountain states, etc.), Dubois (1983) using state-level turnout, and Delli Carpini (1984) using congressional districts.

While Epstein & Strom determined that the results were inconclusive. Both Delli Carpini and Dubois found there to be an effect, but Dubois argued this was a unique effect of the 1980 election. Jackson (1983) was different from the other studies because it was able to address the issue of information access, which the other 3 ignored. Because Jackson used a survey from the University of Michigan’s Presidential Election Study and from the Vote Validation Study by the Center for Political Studies he was able to create a pool of 1814 persons who were interviewed both before and after the election. Jackson found that the combination of access to early election returns and hearing Carter’s concession speech reduced turnout between six and twelve percent. There was little evidence, however, that either party was disproportionately affected, but because of statistical errors and among other problems it decreases confidence in the results.

The most recent study by Peterson (2004) looks to address voter access to information that past studies have ignored. He was able to show a direct effect of early reporting with the average turnout for the informed participants were 31.2%, while it was 71.5% of the uninformed participants.

West Coast Effect Figure showing voter turnout between informed and uninformed participants

The study also found that among informed participants that turnout dropped by 19.1% based off of earlier reports, but favored the candidate that lost on the East Coast because those participants turnout dropped only 8.3%.

West Coast Effect Figure showing voter turnout between favorable news and unfavorable news

The first part of Peterson (2004) study shows us that the West Coast effect occurs, and participants who had access to the early election returns were significantly and consistently more likely to stay home than uninformed participants. In the second part, Peterson (2004) looked at the effect if one candidate always had the support of a majority of the potential voters.

West Coast Effect With one Candidate having support of a majority

The study found when the information supports the majority candidate that informed voters weren’t effective, but uninformed voter turnout decreased slightly from 65% to 59% for majority supporters and decreased from 37% to 25%. When information about the minority candidate shows them winning or tiring on the east coast, then minority supports increase from 33% to 55%, while turnout from the supporters of the majority candidate plummeted from 42% to 13%.

Effect on 2016

While the studies are inconclusive the effect on early reporting does have the possibility to affect the outcome of the race and given a headline during and right after early voting:

Millions of people have voted, and Democrats are showing strong signs in key states

Could Hillary Clinton win the election weeks before November 8?

on top of the early reporting, the voter that did come out to vote were Super Voters so when election day came around and everyone from Fox News to MSNBC said that Clinton was in a strong position to win the low prospect voters decided not to show up.

After the election, a lot has been said about how Donald Trump won, but when looking at what happened in Michigan and Wisconsin with voter turnout dropping 0.2% and 3.4%, respectively the effects of early reporting should be taken seriously even if the results are inconclusive. Moving forward surveys looking to study the West Coast Effect should move beyond early reporting on election day and examine the effects of early reporting from early voting and the effect it has on election day turnout.


Delli Carpini, M. X. (1984). Scooping the voters? The consequence of the networks’ early call of the 1980 presidential race. Journal of Politics, 46, 66-85.

Dubois, P. L. (1983). Election night projections and voter turnout in the west. American Politics Quarterly, 11, 349-63.

Epstein, L. K., & Strom, G. (1981). Election night projections and West Coast turnout. American Politics Quarterly, 9, 479-91

Fuchs, D. A. (1966). Election-day radio-television and voter turnout. Public Opinion Quarterly, 30, 226-37.

Lang, K., & Lang, G. E. (1968). Voting and Nonvoting: Implications of Broadcasting Returns Before Polls Are Closed. Waltham, MA: Blaisdell.

Jackson, J. E. (1983). Election night reporting and voter turnout. American Journal of Political Science, 27, 613-35.

Peterson, G. D. (2004). Can A Voter In New York Make A Candidate Lose in California? An Experimental Test of the Release of Early Election Results On Voter Turnout. Lights, Camera, Campaign!: Media, Politics, and Political Advertising, 11, 73.