Indicators of Socioeconomic Position

Course on Social Determinants of Health

Parvin Tajik, MD

PhD candidate of Epidemiology,

Tehran University of Medical Sciences

SEPWidely used in epidemiological

research:◦Socioeconomic Position (SEP)◦Socioeconomic Status (SES)

Definitions vary but incorporate:◦Physical resources◦Social resources◦Status with the social hierarchy

Its measurement is crucial

Indicators of SEPA multi-dimentional construct

with diverse factors:◦Education◦Occupation◦Economical status

Moderately correlated, but not interchangeable

EducationOne of the most widely used Can be easily determined for all

individualsHealth impairments

that emerge in adulthood rarely affect educational attainment => Avoids the potential contamination of reverse causation

EducationCan reflect a range of non-

economical social characteristics:◦General knowledge◦Health-related knowledge◦Literacy◦Problem-solving skills◦Prestige◦Influence over others & one’s own life

Affects Health

Measurement approaches

)اداره ي طبقه بندي سطح سواد آمار ايران(

بي سواد ابتدايیراهنمايی متوسطه پيش دانشگاهیعالی سوادآموزی بزرگساالن سايردوره های تحصيلی

ComparisonBoth approaches are common

More meaningful to measure educational level in terms of credentials rather than simply years of education: more influential in determining occupational prestige

Advantages

Fairly stable beyond early adulthood

Its measurement is practical and convenient in many contexts

One of the SEP indicators especially likely to capture aspects of lifestyle and behavior

Limitations (1)Varies by birth cohort Relative to income, there is

decreasing variance => may minimize estimates of social inequalities in health

Lack of volatility => precludes the opportunity to assess how health status is affected by changes in SEP

Individualistic, separate from other members of the household

Limitations (2)The economic return for a given

level of education varies importantly by race and gender

The economic and social return for a given level of education may vary importantly by the prestige of the educational institution attended

OccupationSummarizes:

◦Power◦Income ◦educational requirements

associated with various positions in the occupational structure

Several advantages:the outcome of educational attainment

likely to be a better indicator of income over the long term than is income

a promising measure of social position & job characteristics:◦environmental and working conditions, d◦decision-making latitude◦psychological demands of the job.

CODE DESC1 قانونگذاران ، مقامات عاليرتبه ومديران11 قانونگذاران و مقامات عاليرتبه111 قانونگذاران1110 قانونگذاران1110 استاندار1110 بخشدار1110 دادستان كل كشور1110 دبيركل سازمان امورادارئ واستخدامي كشور1110 رهبر1110 رييس جمهور1110 رييس ديوانعالي كشور1110 رييس سازمان انرژئ اتمي1110 رييس سازمان برنامه وبودجه1110 رييس سازمان تربيت بدني1110 رييس سازمان حفاظت محيط زيست1110 رييس شوراعالي قضايي1110 رييس شورائ شهر1110 رييس مجلس شورائ اسالمي1110 رييس مجمع تشخيص مصلحت نظام

تكنسين شنوايي سنجي تكنسين فوريتهائ پزشكي تكنسين كالبدشكافي تكنسين نوارنگارئ تكنسين هوش برئ راديوگراف راديولوژيست - كارشناس ياتكنسين سونوگراف - كارشناس ياتكنسين شنوايي سنجي كارشناس اموربهداشتي ودرماني روستا كارشناس راديولوژئ كمك تكنسين استريل كمك تكنسين راديولوژئ كمك تكنسين نوارنگارئ متخصص اديومترئ متصدئ اتاق عمل

)اداره طبقه بندي گروه شغلی ي آمار ايران(

قانونگذاران، مقامات عالي رتبه ومديران ابتدايی متخصصان تكنسين ها ودستياران كارمندان اموراداري ودفتريکاركنان خدماتي وفروشندگانكاركنان ماهركشاورزي، جنگلداري و ماهيگيريصنعتگران وكاركنان مشاغل مربوط متصديان، مونتاژكاران ماشين آالت و دستگاه ها و

رانندگان وسايل نقليهكارگران ساده

Economical statusDirect measures

◦Income◦Consumption

Indirect measures◦Household assets (Wealth)

Direct measuresIncome:

◦Earnings from productive activities + transfers

Consumption:◦Resources actually consumed

Moderately correlated, but not interchangeable

Correlation between indices

Which of these categories best describes your total combined family income for the past 12 months? This should include income (before taxes) from all sources, wages, rent from properties, social security, disability and/or veteran's benefits, unemployment benefits, workman's compensation, help from relatives (including child payments and alimony), and so on. _____Less than $5,000_____$5,000 through $11,999_____$12,000 through $15,999_____$16,000 through $24,999_____$25,000 through $34,999_____$35,000 through $49,999_____$50,000 through $74,999_____$75,000 and greater_____Don't know_____No response

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ConsumptionPreferred measure by manyDifferent questionnaires with

different items4 main classes of consumption:

◦Food items◦Non-food items◦Consumer durables◦Housing

Consumption expenditure

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0 200000000 400000000 600000000 800000000 1000000000Impure consumption expenditure

3 steps in construction

1. Constructing an aggregate of different components of consumption

2. Making adjustment for cost of living differences

3. Making adjustment for household size and composition

In developing countries Consumption is preferred:

1. Income is received intermittently, consumption smoothed over time => more directly related to current living standards

2. Income data is more difficult to collect. Self-employment Multiple & continually changing sources of

income Informal economic activities Widespread reluctance to disclose

information on income

Proxy measures (wealth)Using household assets & other

characteristics

Data easily collected on a single household interview or observation

Less recall bias & more reliable

Constructing a proxy wealth index

◦3 methods: ◦differ in how household assets &

characteristics are weighted in overall index:

1. Arbitrary2. Predicting consumption3. Principal component analysis

1. Arbitrary approachSum of indicatorsEqual weightsConvenient proxy

Index = asset1 + asset2 + ….+ assetn

Each asset is a dichotomous (0, 1) variable

Very simple wealth index =Very simple wealth index = Vacuum + Kitchen + Computer + Washing + Vacuum + Kitchen + Computer + Washing + Bathroom + FreezerBathroom + Freezer

2. Predicting consumptionWhere complementary data are

availableDeriving weights for index through a

consumption regression => coefficients are used as weights

It has considerable predictive powerCan include Indicators & determinants

Y = w1asset1 + w2asset2 + + wnassetn

Each asset is a dichotomous (0, 1) variable

3. Principal components analysisUsing statistical techniques to

determine the weights in the indexTo describe as much as possible of

the variation in the original data set.Asset index is the first linear

combination

Y = w1asset1 + w2asset2 +…+wnassetn

Each asset is a dichotomous (0, 1) variable

id VariableScoring

Coefficients1 Vacuum cleaner 0.274872 Washing machine 0.255673 Bathroom 0.240784 Kitchen 0.235155 Heating fuel 0.231186 Color TV 0.22117 Telephone 0.220978 Gas 0.215269 Area 0.2093210 Rooms 0.2072211 Housing 0.2039412 Freezer 0.1994513 Mobile 0.1975314 Sewing machine 0.1961315 Computer 0.1867716 Car 0.1837117 Cooler 0.1758618 Recorder 0.1751519 Oven 0.1669720 Video 0.1654921 Cooking fuel 0.1436522 Piped water 0.1427123 Internet 0.1393924 Bicycle 0.1016825 Central heating 0.0926326 Fan 0.0900227 electricity 0.0897728 Mobile cooler 0.0498129 Radio 0.0424830 Motorcycle 0.0323331 Central cooler 0.0302632 Refrigerator 0.0086733 BWTV -0.12393

Constructed WI distribution

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Advantages of incomeCaptures the dynamic component of

SEP Income is the component of SEP that

is most amenable to change through redistributive policies such as tax credits or direct income supplementation

Has psychometric properties of being continuous and spread along a very broad range from low (the depths of poverty) to high (extreme wealth)

Limitations of incomeReverse causation problemMore unstable measure than education or

occupationSensitive to changes in life circumstances Age dependentSensitive for some people => greater

errors in reporting and non-responseCostly and time consuming measurement Varies within occupations and is only

moderately correlated with education Measures fail to include all income earned

Past SE experiences:Effect of childhood SEP on health,

Independent of adult SEP.Importance varies with health

outcomesSEP measurement at only one stage of

life is inadequate for full evaluationCan act as confounder or effect-

modifierChanges of SEP over time can affect

healthPoverty can have cumulative health

effect

Neighborhood SE conditionsCould affect health through

features of the environment:◦Physical◦Social◦Service

% of poor household or Unemployed adults in the region

or physical environment