Opinión Pública y Análisis de Encuestas

1. Opinión Pública y Análisis de Encuestas Módulo VII: Encuestas y elecciones viernes 8 de julio de 2010 David Crow, Associate Director UC Riverside, Survey Research Center david.crow@ucr.edu

2. Polls and Elections(Asher, Chap. 7) • Types of Polls • Who sponsors survey? • What is survey used for? • Campaigns Use of Polls to Influence Voters - Jumping on the bandwagon? • Media Coverage of Campaigns • Off to the races  horse race instead of substantive coverage • Why Polls Go Wrong • Effects of Polls on Elections

3. Types of Polls: Benchmark • Benchmark Surveys: Initial poll to assess candidate viability; serves as baseline against which to measure progress Asks about • Name recognition • Electoral strength vis-à-vis opponent • Support for Incumbent Problems: typically done very early into a campaign, so - people are unlikely to know much about the challenger - economic and political circumstances could change Typically only leaked if they show a candidate doing well

4. Types of Polls: Trial Heat • Trial Heat Questions: Series of questions in a survey that pair candidates in hypothetical races  E.g., “If elections were held today, would you vote for A or B?” Problems: • Abet “horse race” focus of media coverage • Changing circumstances between survey and election day • Is it a measure of candidate or party appeal? Not clear in case of lesser-known candidates • Also, leaves out relevant alternatives  three two-way races (between A and B, B and C, and A and C) not the same as one three-way race • Pairs chosen have “framing effect” on race

5. Types of Polls: Tracking Poll • Tracking Poll: Polls undertaken on a daily basis close to election day  goal is to monitor trends (rises and falls) in support for candidates • Rolling sample: New sample chosen every day, so tendency reported is a “moving average” over several days  “smoothes out” random fluctuation Problems: • extraordinary events could swing preferences wildly for one day, throwing off average over several days • Sometimes volatile in their predictions  small samples could lead to wild fluctuations in, e.g., distribution of party preferences

6. Types of Polls: Focus Groups • Focus Group: in-depth interviews with small group of people chosen to represent broad demographic groups (e.g., “soccer moms”) Used for 1) debate preparation; 2) political marketing; 3) survey item development; 4) gauge public sentiment on issues  e.g., 1992 Willie Horton ad Problems: although they can be a valuable tool, media often fail to recognize methodological limits  not representative; “groupthink”  people’s opinions may be different in a group setting than in isolation

7. Types of Polls: Exit Polls • Exit Poll: Interviews of voters as they leave the polling place; • advantage: we know people actually voted Problems: - Don’t take into account absentee ballots • Non-response bias some groups more willing to participate than others • Social desirability • Do poll results in Eastern states affect outcomes, turnout in the West?  1980 presidential election

8. Types of Polls: “Push” Polls • Push Poll: Tendentious questions that feed misleading or false information to voters in an attempt to sway vote against a candidate  Propaganda disguised as scientific research Protecting against “push polls”: 1) ask for name of organization conducting poll; 2) length of survey greater for legitimate polls; 3) number of calls far higher in a push poll

9. How Candidates Use Polls • Gauge the viability of a candidacy: commission private poll; bad news might dissuade a candidate from running • Get Campaign Donations: news releases of good results as proof of viability, possibility of winning • Bad Results?: cast aspersion on credibility of polls; three common responses: 1) too early to tell; 2) attack pollsters and journalists; 3) counter the results with other polls. Also, question methodology • Manipulate Polls to Promote Candidacy: • Selectively leak results • Tweak survey design to get desired results  • “priming” voters to evaluate candidates on favorable traits • Sample selection • Supplying negative information on opponent

10. Polls and Presidential Selection • Ubiquity of polls in all phases of presidential campaigns  statewide polls in primary states, national polls, etc. • Pollsters become part of campaign team • Strategy based on (or takes into account) poll results • Do polls reflect current state of public opinion, or do they sway vote choice? • Reporting polls results creates “momentum”, and feedback cycles • Affect fund-raising abilities

11. Polls and Presidential Elections • Instant Polls: instantaneous or overnight polls media’s focus on immediate reaction decreases quality of polling • Proportional to number of days in field • Proportional to number of respondents • Interviews only people available at a certain time • Polls as Filters: third-party and lesser-known candidates can’t become known, because they can’t reach threshold (15% in 1980, as set by LWV) of vote preferences to participate or are excluded outright; case of Ross Perot in 1992 • Other standards: national organization, newsworthiness, enthusiasm for candidacies (as demonstrated by polls) • BUT, should just anyone who wants to participate be able to? Debates should not be cluttered with frivolous candidates  who sets and enforces standards? Bipartisan commission is exclusive

12. Media Reporting of Polls • Overemphasis on poll results • Undue magnification of small shifts in preferences  these are random fluctuations, new true changes in preferences • Subtleties of poll methodology go unreported • Media focus on own polls, ignore other pollsters  averages over polls are more accurate than any individual poll

13. Polls’ Effects on Voters • Do polls mobilize or demobilize voters? • “Bandwagon” effect: Polls rally voters behind candidate in lead, discourage people from voting for trailing candidates • “Underdog effect”: voters rally behind candidate who is behind • Evidence: • Experimental designs: poll preferences, expose voters to other poll results, take poll afterwards  inconclusive: de Bock (1976) found evidence of discouragement, Marsh (1984), of underdog effect • Survey questions: ask voters about their exposure to polls, and directly whether polls influence choice; problems  imperfect recall and people unwilling to admit they are influenced by polls • Polls can also have indirect effects  influence campaign contributions, media coverage, other attitudes

14. ¡A veces se equivocan las encuestas electorales!

15. Polls Are Sometimes Wrong! • Most Are Pretty Accurate: however, some notorious mistakes (and run-of-the-mill problems) • Literary Digest 1936 incident  self-selected sample predicted Alf Landon (who?) victory over FDR • 1948 Dewey vs. Truman  quota sampling method (not probability) and premature cut-off to polling predicted Dewey victory, despite narrow lead (5%) and downward trend • 1980 Reagan victory  predicted tight race instead of 10% Reagan landslide; polling failed to pick up last-minute surge in Reagan support among undecideds • 1992 general election  conflicting poll results; criticism over sampling, allocation of undecideds to candidates, shift from “registered” to “likely” voters • 1996 Clinton victory: overestimated margin of victory, widely varying polls for House

16. Why Polls Are Wrong: Timing • The closer a poll is to the election, the more likely it is to be right • Later polls capture effects of last-minute events and campaign activities  Crespi (1988) found this was most important factor, followed by margin of victory (wider margin  more accurate polls) and turnout (higher turnout  more accurate) • Earlier polls are likelier to reflect name recognition of candidates • Polls do better when they 1) do well at identifying likely voters and 2) track voter preferences over time • E.g., Bush Sr.’s win in New Hampshire primaries: • Most polls stopped too early • Tracking polls (CBS) did better at predicted margin of victory • Media focus on own polls, ignore other pollsters  averages over polls are more accurate than any individual poll

17. Why Polls Are Wrong: Undecideds • Three reasons for “undecided” response • Voters genuinely cannot make up minds  lack of information • Unwilling to make choice • Unwilling to reveal choice to pollster • Polls that do not account for undecideds may not yield best predictions • E.g., Wilder race in Virginia (“Wilder effect”) and Dinkins in NY: “undecided” masked race effects in which whites who intended to vote for white candidate (or were talking with black interviewer) said they were “undecided” • Methods for dealing with “undecided” problem: • “Secret ballot” method pioneered by Gallup: simulates real election by giving voters ballot; interviewer does not see choice (only used with face-to-face) • Ignore undecideds and tabulate results only for those who state a preference  problem: some will vote, and they may differ in their choices than those with stated preferences • Allocate undecideds in proportion to preferences  not good when one candidate is more well known than others • Allocate undecideds on other factors, such as party ID, sociodem.

18. Why Polls Are Wrong: Turnout • Likely Voter Problem: which respondents will really vote? “Social Desirability” overestimates probability of voting; Problem  preferences of voters and non-voters are probably different • Methods for assessing likely voters: • Self-reported intention to vote • Registration status • Reported frequency of past voting • Knows where polling site is • Interest in politics • Interest/awareness of campaign • Intensity of candidate preferences • Estimates can be based on only those classified as “likely voters”, or weighted by predicted probability of voting • Different polling agencies use different combinations of these factors

19. Why Polls Are Wrong: Changing Economic and Political Environment • Changing circumstances (economic crisis, campaign intensity, scandal) could motivate some citizens to vote that might other • E.g., 1982 midterm election: polls underestimated Democratic turnout motivated by economic recession  labor unions, ethnic advocacy groups had effective get-out-the-vote (GOTV) operations • E.g., 1994 midterm: Republican “Contract with America”  polls underestimated Republican victory; Clinton campaigns had reverse effect of mobilizing Republicans

20. Pronósticos electorales y votantes probables • Una de lasmetasmássonadas de lasencuestaspreelectoraleses la de pronosticar el resultado electoral. • Sin embargo, ello se complica porque se les entrevista no a quienes van a voter, sino a adultos en edad de votar • Es decir, hay una especie de error de cobertura, porque el marco muestral incluye a personas que no forman parte de la población

21. ¿Cómo determinar los votantes probables?Probabilidad autorreportada de votar • Preguntardirectamentesobre la intención de votar. • La pregunta típica es “Qué tan probable es que Ud. vaya a votar en la próxima elección?” • Definitivamente • Muy probable • Algo probable • Poco probable • Nada probable • 1) se sustrae de la base de datos quienes contestaron de “muy probable” para abajo, p.e., y la pregunta de intención de voto se hace sólo sobre quienes dijeron “definitivamente” O • 2) se asignan valores numéricos (arbitrarios o con base en encuestas previas) a las probabilidades y se realiza una ponderación con base en esas probabilidades

22. ¿Cómo determinar los votantes probables?Participación electoral previo • Se preguntasobresi el entrevistadovotó en la elecciónpasada (o laseleccionespasadas) • Distintos tipos de elecciones: federales, estatales, municipales, etc. • Se le asigna una mayor ponderación a quienes votaron—nuevamente, de forma arbitraria o basándose en información externa (encuestas poselectorales, verificación del voto, etc.)

23. ¿Cómo determinar los votantes probables?Actitudes hacia la política • Se preguntasobre: • Interéspor la política • La atención ha puesto en la campaña electoral, • Si platica de política con otragente • Otrotipo de actividadespolíticas (participar en campañas, contactar a susdiputados, etc.) • Pregunta típica: “¿Qué tanto se interesa Ud. por la política?” • Muy • Algo • Poco • Nada

24. El método de Gallup • Siete preguntas, seis relacionadas con historia de participación electoral y una sobre “qué tanto ha pensado en la próxima elección” • Se asigna un punto a cada pregunta para sacar una escala de 0 a 7. • Basándose en estudios internos de “validación del voto” (en los que personal de Gallup va a los registros locales electorales para cerciorarse de que la gente que dijo que iba a votar, votó—pues la participación electoral es información pública en EE.UU—), se determinó que quienes tenían un puntaje de 7 en la escala, contaban con una probabilidad de votar del 55% porciento. • Se pondera la muestra por esas probabilidades.

25. Otros métodos de evaluar la probabilidad de votar: • Otras encuestas: • Calcular la probabilidad de votar de encuestas poselectorales usando regresión logística multivariada • Usar esas probabilidades para calcular ponderadores • Aplicar los ponderadores a una encuesta preelectoral • Ponderar con información de la población: • El problema de votantes probables es uno de no respuesta diferencial  quienes no van a votar contestan la encuesta en proporción mayor a quienes sí van a votar • Se puede posestratificar una encuesta preelectoral • Definir estratos como edad, sexo, raza, estado, etc. • Usar información del censo (u otra fuente) para saber las proporciones de esas variables en la población • Ajustar las proporciones de la muestra a las de la población

26. Cuadrocomparativo de correccionesparavotantesprobables CD = Citizen Disenchantment (June, 2006, N=509) CD Likely Voter = only those who said they would “definitely” vote MPS = Mexico 2006 Panel Study (May, 2006, N=1,914) MPS Likely Voter = only those who said they were “totally sure” they would vote MPS ID = only those who had a valid voter ID MPS Interest Weights = 2 for “a lot” of interest, 1.33 for “some”, 0.67 for “a little” and 0 for none