High levels of child poverty in New Zealand have been a concern for child poverty advocates, policymakers and, of course, parents of children living in poverty for many years. One of the difficulties in the monitoring and measurement of child poverty, and poverty in general, is the lack of an official poverty measure (or suite of measures) in New Zealand.Using a relative measure, which defines ‘poverty' as being less than 60% of the median disposable household income (before housing costs), it is estimated that around 20% of children are in poverty in New Zealand—this figure has remained static for several years.1 Using a deeper definition of ‘poverty' as being less than 50% of the median disposable household income, then around 12% of children are in poverty.However, these estimates are derived from cross-sectional survey data and do not give any information about children who experience prolonged or repeated periods in poverty. Evidence suggests it is these children, who are exposed to many years of poverty and deprivation, who are at the highest risk of poor outcomes, including poor child development, worse health as children and adults, and lower socioeconomic status as adults.2-6Longitudinal data are needed to show how many New Zealand children are experiencing extended episodes of poverty and which children are most at risk. Currently, such information has not been available due to a lack of suitable survey data. We make use of the New Zealand Survey of Family, Income and Employment (SoFIE), a longitudinal survey which has collected annual income information from a representative sample of households in New Zealand. This is a summary from key results presented in a recently published working paper.7MethodsSurvey data—This analysis uses seven waves of data from SoFIE, which was an annual panel survey administered by Statistics New Zealand (SoFIE data waves 1-7, version 2). SoFIE gathered detailed annual information through face-to-face interviews on income, household and family status, demographic factors and health status from over 18,000 individual sample members, including 4930 children who participated in all 7 years of the survey from 2002 to 2009.The individual child was the unit of observation for this analysis, so if there were two or more children in a household then their household income was represented two or more times in the analysis population. Children aged less than 15 years were not asked specific survey questions, but demographic information (age, sex and ethnicity) on all children in the household was collected from the respondent in the household who answered the household questionnaire.8Income measure—The main measure of income used in the analyses was total nominal (not adjusted for changes in Consumer Price Index) household gross income, before tax and housing costs, derived by totalling adult annual personal income from all sources received within a household and equivalised for household size using the 1988 Revised Jensen Scale.9The measure of low income used in this analysis of SoFIE was 50% or less than the median equivalised gross household income at each wave. We calculated the duration a child was classed as being in low income over the seven waves of the survey period by adding up the number of waves the child was in a household with low income (range: 0 to 7).We present results using <50% of median gross household income because the cross-sectional rates of low income in children using this definition of low income were similar to the known child poverty rate in New Zealand (around 20%, using <60% of median disposable household income, before housing costs).1Disposable (after tax) income was not available from the SoFIE dataset at the time of this analysis. Low income prevalence using the <60% threshold is presented as a comparison.Other variables—Analyses were done for all children (0-17 years) and also by 0-4, 5-9 and 10-17 year age groups.The age variable used was age at wave 1, therefore by wave 7 the children will have aged by 7 years (e.g. by wave 7, the group of children will be aged 6 to 23 years). However, it is important when using longitudinal data to follow the same cohort of individuals even as the age, in order to track their changes over time.Other descriptive variables included sex, ethnicity (Māori, Pacific and Other, where ‘Other' includes NZ European, Asian and Other ethnic groups), family structure and area deprivation, based on New Zealand Index of Deprivation 2001 , which assigns small geographic areas a ranking based on the average deprivation characteristics of people living there.10Caveats and cautions—The numbers presented in the tables were rounded to base 5 due to Statistics New Zealand confidentiality protocols. Results were not weighted to the New Zealand population and relate only to the SoFIE survey balanced panel sample. No statistical tests for differences between groups or trends over time were conducted. Although the sample size of children for this analysis is moderate (over 4000), any proportions or percentages that were based on cell numbers of 10 or less are highlighted in bold in the tables, and these should be interpreted with caution.ResultsTable 1 presents cross-sectional rates of low income at each wave for children aged 0 to 17 years at wave 1 and by age subgroups. Between 18 and 21% of the whole child SoFIE population were in low income across the seven waves. Using the <60% of median income threshold for low income, between 26 and 30% of children were in low income across the 7 waves.A small decrease in the proportion of the child population who were in low income over the study period, which was consistent across all demographic groups, is likely to be due to the introduction of a significant social policy aimed at reducing poverty in low income households, the Working For Families tax credit package.11 The low income rates were higher in Māori and Pacific children, which is consistent with other research.1Table 2 presents the number of waves children were in low income across the study period. This shows that 47% of children experienced low income at least once during the 7 waves. Sixteen percent of children were in low income for over half of the study period (4 or more years), which we define as experiencing persistent low income.There were higher rates of persistent low income in Māori and Pacific children (23% and 29% respectively), children living in sole parent families (34%) and children from the most deprived neighbourhoods (28%). Thirteen percent of children who started out in low income households at wave one remained in low income for all 7 waves and over half of these children experienced persistent low income. Table 1. Percentage of the population in low income at each wave Characteristics Total W1 W2 W3 W4 W5 W6 W7 N % in low income (<50% of median income) All 4930 21.0 20.1 19.9 18.3 18.3 18.3 19.2 Age at wave 1 (years) 0 to 4 1355 20.7 20.7 22.1 20.3 19.6 17.0 19.2 5 to 9 1535 23.8 22.1 19.9 17.6 16.0 16.6 17.6 10 to 17 2040 19.1 18.1 18.4 18.4 19.1 20.3 20.3 Ethnicity Māori 1045 32.1 31.6 29.2 26.8 23.9 24.4 25.4 Pacific 295 37.3 30.5 33.9 25.4 25.4 27.1 27.1 NZ European\/ Other 3590 16.6 15.7 16.0 15.7 15.9 15.7 16.7 N % in low income (<60% of median income) All 4930 29.6 29.0 27.5 25.7 26.1 25.5 26.0 Age at wave 1 (years) 0 to 4 1355 31.4 30.6 31.0 27.7 28.4 26.2 27.3 5 to 9 1535 31.3 32.6 28.7 26.4 24.4 24.1 25.1 10 to 17 2040 27.2 25.2 24.3 23.8 25.7 26.0 25.7 Ethnicity Māori 1045 43.1 41.1 38.3 36.4 35.4 33.0 35.4 Pacific 295 44.1 42.4 47.5 39.0 37.3 37.3 30.5 NZ European\/ Other 3590 24.7 24.7 22.7 21.6 22.4 22.4 22.8 Income based on gross equivalised household income (not CPI adjusted and before housing costs). Table 2. Characteristics of respondents by number of waves the population experiences low income (<50% of median household income) Characteristics Waves in low income 0 1 2 3 4 5 6 7 Overall age 0-17 4930 53.3 14.9 9.2 7.3 5.7 4.3 2.8 2.7 Age at wave 1 (years) N Row% 0 to 4 1355 55.4 12.9 7.7 6.6 5.9 4.8 3.7 3.0 5 to 9 1535 57.3 13.0 6.8 7.2 5.2 4.2 2.9 3.9 10 to 17 2040 49.0 17.6 12.0 7.8 5.9 3.9 2.2 1.7 Sex Male 2495 53.3 15.4 9.6 7.4 5.2 4.4 2.4 2.4 Female 2435 53.2 14.2 9.0 7.2 6.0 4.1 3.3 2.9 Ethnicity Māori 1045 42.1 12.4 12.0 11.0 6.7 5.7 4.8 5.7 Pacific 295 40.7

High levels of child poverty in New Zealand have been a concern for child poverty advocates, policymakers and, of course, parents of children living in poverty for many years. One of the difficulties in the monitoring and measurement of child poverty, and poverty in general, is the lack of an official poverty measure (or suite of measures) in New Zealand.Using a relative measure, which defines ‘poverty' as being less than 60% of the median disposable household income (before housing costs), it is estimated that around 20% of children are in poverty in New Zealand—this figure has remained static for several years.1 Using a deeper definition of ‘poverty' as being less than 50% of the median disposable household income, then around 12% of children are in poverty.However, these estimates are derived from cross-sectional survey data and do not give any information about children who experience prolonged or repeated periods in poverty. Evidence suggests it is these children, who are exposed to many years of poverty and deprivation, who are at the highest risk of poor outcomes, including poor child development, worse health as children and adults, and lower socioeconomic status as adults.2-6Longitudinal data are needed to show how many New Zealand children are experiencing extended episodes of poverty and which children are most at risk. Currently, such information has not been available due to a lack of suitable survey data. We make use of the New Zealand Survey of Family, Income and Employment (SoFIE), a longitudinal survey which has collected annual income information from a representative sample of households in New Zealand. This is a summary from key results presented in a recently published working paper.7MethodsSurvey data—This analysis uses seven waves of data from SoFIE, which was an annual panel survey administered by Statistics New Zealand (SoFIE data waves 1-7, version 2). SoFIE gathered detailed annual information through face-to-face interviews on income, household and family status, demographic factors and health status from over 18,000 individual sample members, including 4930 children who participated in all 7 years of the survey from 2002 to 2009.The individual child was the unit of observation for this analysis, so if there were two or more children in a household then their household income was represented two or more times in the analysis population. Children aged less than 15 years were not asked specific survey questions, but demographic information (age, sex and ethnicity) on all children in the household was collected from the respondent in the household who answered the household questionnaire.8Income measure—The main measure of income used in the analyses was total nominal (not adjusted for changes in Consumer Price Index) household gross income, before tax and housing costs, derived by totalling adult annual personal income from all sources received within a household and equivalised for household size using the 1988 Revised Jensen Scale.9The measure of low income used in this analysis of SoFIE was 50% or less than the median equivalised gross household income at each wave. We calculated the duration a child was classed as being in low income over the seven waves of the survey period by adding up the number of waves the child was in a household with low income (range: 0 to 7).We present results using <50% of median gross household income because the cross-sectional rates of low income in children using this definition of low income were similar to the known child poverty rate in New Zealand (around 20%, using <60% of median disposable household income, before housing costs).1Disposable (after tax) income was not available from the SoFIE dataset at the time of this analysis. Low income prevalence using the <60% threshold is presented as a comparison.Other variables—Analyses were done for all children (0-17 years) and also by 0-4, 5-9 and 10-17 year age groups.The age variable used was age at wave 1, therefore by wave 7 the children will have aged by 7 years (e.g. by wave 7, the group of children will be aged 6 to 23 years). However, it is important when using longitudinal data to follow the same cohort of individuals even as the age, in order to track their changes over time.Other descriptive variables included sex, ethnicity (Māori, Pacific and Other, where ‘Other' includes NZ European, Asian and Other ethnic groups), family structure and area deprivation, based on New Zealand Index of Deprivation 2001 , which assigns small geographic areas a ranking based on the average deprivation characteristics of people living there.10Caveats and cautions—The numbers presented in the tables were rounded to base 5 due to Statistics New Zealand confidentiality protocols. Results were not weighted to the New Zealand population and relate only to the SoFIE survey balanced panel sample. No statistical tests for differences between groups or trends over time were conducted. Although the sample size of children for this analysis is moderate (over 4000), any proportions or percentages that were based on cell numbers of 10 or less are highlighted in bold in the tables, and these should be interpreted with caution.ResultsTable 1 presents cross-sectional rates of low income at each wave for children aged 0 to 17 years at wave 1 and by age subgroups. Between 18 and 21% of the whole child SoFIE population were in low income across the seven waves. Using the <60% of median income threshold for low income, between 26 and 30% of children were in low income across the 7 waves.A small decrease in the proportion of the child population who were in low income over the study period, which was consistent across all demographic groups, is likely to be due to the introduction of a significant social policy aimed at reducing poverty in low income households, the Working For Families tax credit package.11 The low income rates were higher in Māori and Pacific children, which is consistent with other research.1Table 2 presents the number of waves children were in low income across the study period. This shows that 47% of children experienced low income at least once during the 7 waves. Sixteen percent of children were in low income for over half of the study period (4 or more years), which we define as experiencing persistent low income.There were higher rates of persistent low income in Māori and Pacific children (23% and 29% respectively), children living in sole parent families (34%) and children from the most deprived neighbourhoods (28%). Thirteen percent of children who started out in low income households at wave one remained in low income for all 7 waves and over half of these children experienced persistent low income. Table 1. Percentage of the population in low income at each wave Characteristics Total W1 W2 W3 W4 W5 W6 W7 N % in low income (<50% of median income) All 4930 21.0 20.1 19.9 18.3 18.3 18.3 19.2 Age at wave 1 (years) 0 to 4 1355 20.7 20.7 22.1 20.3 19.6 17.0 19.2 5 to 9 1535 23.8 22.1 19.9 17.6 16.0 16.6 17.6 10 to 17 2040 19.1 18.1 18.4 18.4 19.1 20.3 20.3 Ethnicity Māori 1045 32.1 31.6 29.2 26.8 23.9 24.4 25.4 Pacific 295 37.3 30.5 33.9 25.4 25.4 27.1 27.1 NZ European\/ Other 3590 16.6 15.7 16.0 15.7 15.9 15.7 16.7 N % in low income (<60% of median income) All 4930 29.6 29.0 27.5 25.7 26.1 25.5 26.0 Age at wave 1 (years) 0 to 4 1355 31.4 30.6 31.0 27.7 28.4 26.2 27.3 5 to 9 1535 31.3 32.6 28.7 26.4 24.4 24.1 25.1 10 to 17 2040 27.2 25.2 24.3 23.8 25.7 26.0 25.7 Ethnicity Māori 1045 43.1 41.1 38.3 36.4 35.4 33.0 35.4 Pacific 295 44.1 42.4 47.5 39.0 37.3 37.3 30.5 NZ European\/ Other 3590 24.7 24.7 22.7 21.6 22.4 22.4 22.8 Income based on gross equivalised household income (not CPI adjusted and before housing costs). Table 2. Characteristics of respondents by number of waves the population experiences low income (<50% of median household income) Characteristics Waves in low income 0 1 2 3 4 5 6 7 Overall age 0-17 4930 53.3 14.9 9.2 7.3 5.7 4.3 2.8 2.7 Age at wave 1 (years) N Row% 0 to 4 1355 55.4 12.9 7.7 6.6 5.9 4.8 3.7 3.0 5 to 9 1535 57.3 13.0 6.8 7.2 5.2 4.2 2.9 3.9 10 to 17 2040 49.0 17.6 12.0 7.8 5.9 3.9 2.2 1.7 Sex Male 2495 53.3 15.4 9.6 7.4 5.2 4.4 2.4 2.4 Female 2435 53.2 14.2 9.0 7.2 6.0 4.1 3.3 2.9 Ethnicity Māori 1045 42.1 12.4 12.0 11.0 6.7 5.7 4.8 5.7 Pacific 295 40.7