Spanish exit polls. Sampling error or nonresponse bias?

  1. Jose M. Pavía 1
  2. Elena Badal 1
  3. Belén García-Cárceles 1
  1. 1 Universidad de Valencia, España
Revista:
Revista internacional de sociología

ISSN: 0034-9712

Año de publicación: 2016

Volumen: 74

Número: 3

Tipo: Artículo

DOI: 10.3989/RIS.2016.74.3.043 DIALNET GOOGLE SCHOLAR lock_openAcceso abierto editor

Otras publicaciones en: Revista internacional de sociología

Objetivos de desarrollo sostenible

Resumen

Existe un gran número de ejemplos de predicciones inexactas obtenidas a partir tanto de encuestas pre-electorales como de encuestas a pie de urna a lo largo del mundo. La presencia de tasas de no-respuesta diferencial entre distintos tipos de electores ha sido la principal razón esgrimida para justificar las proyecciones erróneas en las encuestas a pie de urna. En problemas de inferencia rara vez es posible comparar estimaciones y valores reales. Las predicciones electorales son una excepción. La comparación entre estimaciones y resultados finales puede realizarse una vez los votos han sido contabilizados. En este trabajo, examinamos los datos brutos recogidos en siete encuestas a pie de urna realizadas en España y testamos la hipótesis de que los datos recolectados en cada punto de muestreo puedan ser considerados una muestra aleatoria de los resultados realmente registrados en el correspondiente colegio electoral. Conocer la respuesta a esta pregunta es relevante para analistas y encuestadores electorales, ya que, si se rechaza la hipótesis, las deficiencias de los datos recogidos deberían ser subsanadas en concordancia. Los analistas podrían mejorar la calidad de sus estimaciones mediante la implementación de estrategias de corrección local. En nuestro estudio encontramos una fuerte evidencia de errores ajenos al muestreo en las encuestas a pie de urna en España y constatamos la importancia del contexto político. El sesgo de no-respuesta es mayor en elecciones polarizadas y en un clima de violencia o presión.

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Información de financiación

Support from the Spanish Ministry of Economics and Competitiveness through project CSO2013-43054-R is also acknowledged.

Financiadores

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