Methodological Foundations of the Web-based PayWizard Dataset (USA) Isabelle Ferreras (Harvard Labor and Worklife Program/FNRS/Louvain) Damian Raess (MIT) Members of the team headed by Prof. Richard Freeman (HarvardLWP/NBER)

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Methodological Foundations of the Web-based
PayWizard Dataset (USA) Isabelle Ferreras
(Harvard Labor and Worklife Program/FNRS/Louvain)
Damian Raess (MIT) Members of the team headed by
Prof. Richard Freeman (HarvardLWP/NBER)

• - A 5 Minute Presentation -
• 3rd Global WageIndicator Conference. Amsterdam,
  April 16, 2008

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General Approach

• How to generalize from a non-representative
  sample?
• Building a strategy to probe the significance of
  the web-generated dataset
• 1/ Questionnaire design
• 2/ Basic statistical tests (a simple model
  determining income)
• 2.a. Correlation analysis
• 2.b. Regression analysis
• 2.c. Weighing might not be enough
• 3/ More to come... With YOU!
• 18 months after launching, a tough road in the
  US a highly competitive market now 10 000
  visitors a month, waiting for completed surveys!
• Number of observations so far 3000

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1/ Questionnaire design

• 1/ Locate the reference survey in your country
• a random sample representative of the entire US
  population
• In the USA US Current Population Survey
  (generated by the Bureau of Labor Statistics and
  the Census Bureau)
• 2/ Identify the questions of the WageIndicator
  survey that correspond to questions covered by
  that reference survey, and aim at matching
  these.
• Example the wage question(s) should be conformed
  to the one of your reference survey.

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2/ Basic statistical tests

• A simple model determining income by age, sex,
  education
• Descriptive variables
• Sex, percentage of men CPS, 51 PayW, 54
• Age, median CPS, 41 PayW, 37
• Education, years of schooling

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2/ Basic statistical tests

• Weekly wage (logwage)

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2/ Basic statistical tests

• A simple model determining income
• 2.a. Correlation analysis

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2/ Basic statistical tests

• A simple model determining income
• 2.b. Regression analysis

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2/ Basic statistical tests

• A simple model determining income
• 2.b. Regression analysis

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2/ Basic statistical tests

• - 2.b. Regression analysis

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Conclusion Weighing might not be enough
3/ More to come... We need YOU!

• A collaborative effort...
• THANK YOU !
• raess_at_mit.edu iferreras_at_law.harvard.edu