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« Les sondages sont des ressorts essentiels de la dramaturgie des campagnes électorales » Gérard Courtois, éditorialiste au « Monde », a répondu aux questions des internautes après la publication de notre huitième vague d’enquête électorale menée par le Cevipof et réalisée par Ipsos-Sopra Steria.

« Les sondages sont des ressorts essentiels de la dramaturgie des campagnes électorales »

Gérard Courtois, éditorialiste au Monde, a répondu aux questions des internautes après la publication de notre huitième vague d’enquête électorale menée par le Cevipof et réalisée par Ipsos-Sopra Steria. Lire aussi : Juppé, Sarkozy, Fillon : une finale à trois pour la primaire de la droite Jacques : Comment peut-on mesurer l’impact des sondages sur les électeurs ? Grâce à d’autres sondages ? Gérard Courtois : En période de campagne électorale, les sondages d’intention de vote sont une drogue dure qui rend fou tout le monde ! Cet engouement n’est pas surprenant : qu’on le veuille ou non, les sondages sont devenus des ressorts essentiels des campagnes électorales et de leur dramaturgie. Il faut d’abord rappeler des éléments essentiels pour tout sondage.

Ça me parait peu vraisemblable. Is Nate Silver right? Polling averages and forecast models are supposed to bring order to the chaos, put outlier polls in proper perspective and provide a sober, unbiased picture of the state of the presidential race.

Is Nate Silver right?

So why are they all over the place in the final days, with some models asserting a Hillary Clinton victory is a near-certainty, and others giving Donald Trump a real chance at winning? Story Continued Below The dissonance has resulted in fundamental disagreements over how close the race really is in a presidential election that both parties have described, in no uncertain terms, as the most important election in our lifetimes.

The latest RealClearPolitics projections have the race teetering on a knife’s edge. But other, more complex forecast models — based on the same polls — give Clinton a 98 percent or 99 percent chance of defeating Trump next Tuesday. In the middle are models from two high-profile data-journalism sites, FiveThirtyEight and The New York Times’ Upshot. The Savvy Person’s Guide to Reading the Latest Polls. Look at the Topline When a poll comes out, I start by looking at the topline results — Hillary Clinton is plus 3 percentage points, or Donald J.

The Savvy Person’s Guide to Reading the Latest Polls

Trump is plus 1, for example. But it’s also worth looking at vote share — whether Mrs. Clinton has 47 percent or 40 percent, for instance. In particular, I care about how close the leading candidate is to 50 percent. There’s more uncertainty the further a candidate is from 50 percent and the larger the number of undecided voters. Until a candidate approaches 50 percent, it’s hard to know whether the lead is because of party unity or because the candidate has won over the key voters needed for victory. There was a good example of this in the Arizona Senate race. Usually, anything at 46 percent or above is a good indicator of real strength.

. ■ It’s also worth looking at whether there’s a difference between registered and likely voters. . ■ This year, there’s also the question of whether to look at four-way or two-way polls. How One 19-Year-Old Illinois Man Is Distorting National Polling Averages. Alone, he has been enough to put Mr.

How One 19-Year-Old Illinois Man Is Distorting National Polling Averages

Trump in double digits of support among black voters. He can improve Mr. Trump’s margin by 1 point in the survey, even though he is one of around 3,000 panelists. He is also the reason Mrs. Clinton took the lead in the U.S.C. How has he made such a difference? It’s worth noting that this analysis is possible only because the poll is extremely and admirably transparent: It has published a data set and the documentation necessary to replicate the survey. Not all of the poll’s choices were bound to help Mr. Tiny Groups, Big Weights Just about every survey is weighted — adjusted to match the demographic characteristics of the population, often by age, race, sex and education, among other variables. The U.S.C. ■ It weights for very tiny groups, which results in big weights. A typical national survey usually weights to make sure it’s representative across pretty broad categories, like the right number of men or the right number of people 18 to 29.

Why You Shouldn’t Trust ‘Polls’ Conducted Online.