An assessment of the robustness of weights in the Famille et Employeurs survey

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An assessment of the robustness of weights in the
Famille et Employeurs survey
Nicolas Razafindratsima (razafind_at_ined.fr)
Elisabeth Morand (Elisabeth.Morand_at_ined.fr) INED
European Conference on Quality in Official
Statistics, Rome, July 2008
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Outline

• Introduction
• The Famille et Employeurs survey
• Methodology of weights calculations
• Results
• Conclusion

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Introduction

• In indirect sampling the generalized weight
  share method (Lavallée, 2002 2007) is a simple
  and easy strategy to produce unbiased estimations
• Objective of this study to expose the
  implementation of this method for the Familles et
  Employeurs survey (Ined/Insee, 2004-2005)
  difficulties, and robustness of the weights
  obtained.

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The Familles et Employeurs survey

• Main purpose to study professional and family
  life conciliation - from the employees point
  of view - from the employers point of view
• Can behaviours within the family be explained
  through employers rules and characteristics?
• A matched survey employee ? employers

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The household survey

• Sampling strategy - a sample of 11 719
  dwellings drawn from the INSEE master sample ? 6
  167 of them answered
• - interview of 1 or 2 individuals, aged 20-49,
  in each household (random sampling if gt2) ? 9 547
  respondents
• Face to face interview. Questionnaire on
  demographic events (birth, unions), family life
  organization, etc., in relation to individuals
  professional context

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The establishment survey

• Target Establishments of 20 employees or more
• Individuals respondents were asked to give their
  employers name, address, national identification
  number as well as their size and sector.
• A self administered questionnaire was sent to the
  establishments. Possibility to answer by paper or
  by the Internet. 2 673 respondents.

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Weighting methodology

• The basic for establishments weighting
  methodology the generalized weight share method

Where Wiweight of establishment i
Wjweight of individual j (those in the
sample) Li number of eligible employees (aged
20-49) in the establishment i
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Weighting methodology

• Difficulties
• - the choice of individuals weight
  (non-response, calibration)
• - the estimation of the number of employees aged
  20-49 in the establishment
• - establishment non-responses

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Weighting the sample of individuals

• Non response variations
• At the household level (non-response higher in
  urban areas, for collective dwellings, etc.)
• At the individual level (non-response higher for
  males, single persons, less-educated people,
  etc.)
• Non-response adjustments
• At the household level using corrective
  response rates within response homogeneity groups
• At the individual level calibration (on Labor
  force survey data)
• - on a single variable genderage
• - or on 7 variables genderage, employment
  status, nationality, region, highest diploma,
  urbanization status, household size

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Distribution of individuals weights
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Estimation of the number of eligible employees
(aged 20-49)

• Number of employees (total and by age groups)
  asked in the establishment questionnaire
• But number of 20-49 not available for 16 of the
  establishments (item non-response)
• Imputation of number of 20-49 when non-response
  using coefficients of a regression model among
  respondents, linking nb of 20-49 to total (one
  model by activity sector)
• For 2/3 of the establishments, total size is also
  available through the SIRENE directory. Allows an
  other estimation of 20-49 number for evaluation
  purposes

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Distribution of total size
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Distribution of number of 20-49
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Summary of the options for establishments
weighting
Employees weightestablishment weightnb of
employees
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Distribution of establishment weights
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Distribution of employees weight
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Percentage of establishments having a crèche
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Percentage of employees working in an
establishment with a crèche
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Conclusion

• Weight sharing method
• A simple and easy to implement method
• However, difficult to implement in the Famille et
  Employeurs survey, due to
• non-responses on the link variable
• High dispersion of the size variable
• More sensitive to the link variable than on
  specification of the individual weights
• All the computed weights present great
  variability
• Weight trimming may improve precision at the
  establishment level, but fails to do so at the
  employees level

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References

• Lavallée, P. (2002) Le sondage indirect, ou la
  méthode généralise du partage des poids,
  Bruxelles, Presses de luniversité libre de
  Bruxelles et Paris, Ellipses, 242 pages.
• Lavallée, P. (2007) Indirect sampling, New
  York, Springer (Springer series in statistics),
  245 pages.

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Thank you for your attention !