The document discusses challenges in conducting cross-national research on socioeconomic status (SES) and child development. It is difficult to find truly comparable measures across countries due to differences in how data is collected. The researcher discusses how they addressed this by selecting common SES measures like income quintiles and harmonizing variables to prioritize comparability over using country-specific measures. Their research found SES gaps in school readiness vary between countries and that most factors like these are already present before school entry, especially in the US. The researcher advocates being transparent about harmonization decisions and how sensitive results are to alternative measurements.

1. The comparability challenge:
Lessons from cross-national
research in developed countries
Jane Waldfogel
October 14, 2014
Funding from NICHD,
Russell Sage Foundation,
& Sutton Trust.

2. Overview
• Drawing on cross-national research on
socioeconomic status (SES) and child
development in 4 developed countries
(Bradbury, Corak, Waldfogel, &
Washbrook), I will discuss
challenges/lessons related to:
- comparability & harmonization
- transparency & sensitivity

3. Research questions
• Do socioeconomic status (SES) gaps in
school readiness, and the factors that
explain them, differ across countries?
• Do these gaps widen or narrow after
school entry, and does this vary across
countries?

4. The challenge
• To answer these questions, we need
comparable measures of SES, child
outcomes, and other predictors/covariates
• But datasets don’t always use same
measures
• So what can we do?
• Tension between best measures vs. most
comparable ones
• Important to be clear about how data are
harmonized and also how sensitive results
are to decisions about

5. Measurement of SES
(e.g. income or education)
• Income
- Continuous or banded? Gross or net?
Includes near-cash/in-kind transfers?
Equivalized?
• Be clear how it’s being defined and how
it’s being made comparable
• We use income quintiles because they
have a similar meaning across countries
• But one might also be interested in
absolute income or other measures (e.g.

6. Measurement of SES
• Parental education
- Mother’s? Father’s? Years of schooling?
Education completed? Certificate
obtained?
• Again, need to be clear how it’s measured
• We use education of most highly educated
parent and 3 ISCED categories that are
comparable across our 4 countries
• We report how/why we created those
categories and how sensitive results are

7. Measurement of child
development
• We need measures of child cognitive
development, behavior, and health
• Sometimes same measure is used across
2+ countries, but rarely all 4
• So we look at each measure and choose
the ones that are most consistent
(sometimes this involves creating our own
measure)
• We report the sensitivity of our results to
using different measures

8. Other covariates
• We also need measures for key predictors
other than SES – variables such as
parenting, parental health/mental health,
etc.
• Often, this means using the lowest
common denominator – rather than the
rich variables available in some datasets –
but this is a necessary trade-off to ensure
comparability.
• But again we report how/why we did this,
and report how sensitive results are

9. Comparing SES gaps in US and
UK
• Using data from ECLS-B (US) and
ALSPAC (UK), Liz Washbrook and I
examined SES gaps in school readiness
• We divided families into income quintiles
and examined bottom-middle (Q1-Q3) and
top-middle (Q5-Q3) gaps in comparable
cognitive outcomes
• We found sizable SES-related gaps in
school readiness (vocabulary) in both
countries, but larger at the top in US than
UK

10. Comparing SES gaps in school
readiness in US & UK

11. Decomposing factors
associated with gaps in the two
countries
• We next used the rich data from the US &
UK cohort studies to examine factors
explaining gaps
• To play a role in explaining gaps, a factor
must
- Differ between income groups
- Have an effect on the outcome
• Our decomposition analysis shows which
factors are most consequential, pointing to
an important role for parenting in both

12. Trajectories after school entry
• We would like to know what happens to
these gaps once children are in school
• Do the gaps widen, narrow, or hold
constant?
• Katherine Magnuson, Liz Washbrook, and
I examined this for US and UK, using data
on reading from ECLS-K and ALSPAC

13. SES gaps after school entry in
US

14. SES gaps after school entry in
UK

15. Gaps in the 4 countries
• In recent work funded by Russell Sage
Foundation, we used 4 longitudinal datasets:
- AU (LSAC), CA (NLSCY), UK (MCS), US
(ECLS-K)
• We follow children from school entry to at
least age 11, analyzing whether SES-related
gaps widen, hold constant, or narrow, and
relating differences in gaps across countries
to differences in family resources & policy
contexts

16. Gaps in the 4 countries
• We find gaps are largest in US, and UK,
and smallest in Australia and Canada
• We are also able to estimate how much of
the gaps at age 11 are already present at
age 5, and how much develops during the
school years
• We find that most of the gap in US is
already present at school entry, more so
than in the other countries

17. Key findings
• Achievement gaps at school entry differ
across countries, mirroring differences in
adult social mobility – with larger gaps in
US & UK than AU & CN
• The evolution of the gaps after school
entry also differs across countries, likely
reflecting the continuing influence of family
factors as well as differences in school
factors

18. Key lessons in terms of
comparability
• It’s important to get the harmonization right
- You have to invest considerable
time/resources in harmonizing data
- You may want to consult others on this
• It’s also important to be transparent
- Be clear what decisions you made and
why
- Be clear how sensitive results are to
alternatives

19. What’s next?
• Examining gaps at school entry, and
evolution of gaps after school entry, in
additional countries
• Examining changes in gaps for
succeeding cohorts, both within and
across countries

20. References
• Bradbury, Bruce, Miles Corak, Jane Waldfogel, & Elizabeth
Washbrook (2012). “Inequality during the Early Years: Child
Outcomes and Readiness to Learn in Australia, Canada, United
Kingdom, and United States.” In John Ermisch, Markus Jantti, and
Timothy Smeeding (eds). From Parents to Children: The
Intergenerational Transmission of Advantage. New York: Russell
Sage Foundation.
• Bradbury, Bruce, Miles Corak, Jane Waldfogel, & Elizabeth
Washbrokk (under review). Too many children left behind: A cross-national
perspective on the US achievement gap. New York:
Russell Sage Foundation.
• Magnuson, Katherine, Jane Waldfogel, & Elizabeth Washbrook
(2012). “The Development of SES Gradients in Skills during the
School Years: Evidence from the United States and England.” In
John Ermisch, Markus Jantti, and Timothy Smeeding (eds). From
Parents to Children: The Intergenerational Transmission of
Advantage. New York: Russell Sage Foundation.

21. References
• Waldfogel, Jane & Elizabeth Washbrook (2011). “Income-Related
Gaps in School Readiness in the United States and United
Kingdom.” In Timothy Smeeding, Robert Erikson, and Markus Jantti
(eds). Persistence, Privilege, and Parenting: The Comparative Study
of Intergenerational Mobility. New York: Russell Sage Foundation.
• Waldfogel, Jane & Elizabeth Washbrook (2011). “Early Years
Policy.” Child Development Research 2011: 1-12.
• Washbrook, Elizabeth, Jane Waldfogel, Bruce Bradbury, Miles
Corak, & Ali Akbar Ghanghro (2012). “The Development of Young
Children of Immigrants in Australia, Canada, the United Kingdom
and the United States.” Child Development 83(5): 1591-1607.