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9 Appendix B

9.1 Representativeness at baseline and sample attrition

A primary goal for the sample selection process of any national study is to ensure that the final sample accurately represents the national population which it is intended to reflect. Table 1 illustrates the degree to which the HWR Māori and non-Māori sub-samples from the baseline survey in 2006 reflect the demographic characteristics of the New Zealand 55 to 70 year old Māori and non-Māori populations, as per demographic data from the 2006 New Zealand National Census (Statistics New Zealand, 2011).[13]

Table 12 shows that both the HWR baseline sub-samples (Māori and non-Māori ) align closely with their respective New Zealand populations, as evident in the proportions of (1) participants across age groups, (2) men and women, (3) those in full time work, and (4) those with no secondary-school qualifications. However, in comparison to their respective populations, the HWR baseline sub-samples both have perceptibly higher proportions than expected of people who are (1) currently in relationships (partnered), (2) in part-time work versus retired/other, (3) tertiary educated, and (4) earning above $20,000. In this regard, as opposed to the New Zealand population aged 55-70, the HWR sample in general reflects a disproportionately greater number of New Zealanders who are still working.

Table 12 – Demographic characteristics of HWR sample at baseline (2006) in comparison with their age-matched New Zealand populations
	Māori		Non-Māori
	HWR sample	NZ 55-70	HWR sample	NZ 55-70
Sex
Male	44.12%⁽¹³⁶⁹⁾	47.61%^(20544)	47.01%⁽¹⁶⁰³⁾	49.12%^(255735)
Female	55.88%⁽¹⁷³⁴⁾	52.39%^(22608)	52.99%⁽¹⁸⁰⁷⁾	50.88%^(264870)
Age (year groups)
55-59	41.36%⁽¹¹⁸⁷⁾	43.18%^(18633)	38.82%⁽¹²³⁵⁾	39.53%^(205779)
60-64	30.56%⁽⁸⁷⁷⁾	29.69%^(12810)	32.25%⁽¹⁰²⁶⁾	30.73%^(159975)
65-70	28.08%⁽⁸⁰⁶⁾	27.13%^(11709)	28.92%⁽⁹²⁰⁾	29.74%^(154854)
Marital status
Partnered	63.97%⁽¹⁹⁸⁵⁾	53.86%^(21726)	76.56%⁽²⁶¹⁶⁾	70.76%^(359592)
Separated	16.82%⁽⁵²²⁾	22.49%⁽⁹⁰⁷²⁾	12.47%⁽⁴²⁶⁾	16.58%^(84267)
Widowed	12.60%⁽³⁹¹⁾	15.15%⁽⁶¹¹¹⁾	6.91%⁽²³⁶⁾	7.49%^(38088)
Never married	6.61%⁽²⁰⁵⁾	8.49%⁽³⁴²⁶⁾	4.07%⁽¹³⁹⁾	5.17%^(26265)
Work status
Working full-time	41.49%⁽¹²¹⁷⁾	41.37%^(17850)	42.17%⁽¹⁴⁶⁰⁾	44.01%^(229107)
Working Part-time	19.62%⁽⁵⁶²⁾	13.85%⁽⁵⁹⁷⁶⁾	22.62%⁽⁷⁶⁵⁾	15.50%^(80715)
Unemployed	2.44%⁽⁷⁰⁾	2.63%⁽¹¹³⁴⁾	1.03%⁽³⁵⁾	1.28⁽⁶⁶⁶³⁾
Other (including retired)	35.44%⁽¹⁰¹⁵⁾	42.15%^(18189)	33.18%⁽¹¹²²⁾	39.21%^(204126)
Educational qualifications
No secondary	57.01%⁽¹⁵⁰⁸⁾	57.35%^(20514)	38.50%⁽¹¹⁶⁰⁾	35.15%^(169314)
Secondary	9.72%⁽²⁵⁷⁾	21.08%⁽⁷⁵³⁹⁾	15.07%⁽⁴⁵⁴⁾	29.95%^(144240)
Post-secondary	12.25%⁽³²⁴⁾	8.60%⁽³⁰⁷⁵⁾	15.50%⁽⁴⁶⁷⁾	11.16%^(53775)
Tertiary	21.02%⁽⁵⁵⁶⁾	12.97%⁽⁴⁶⁴¹⁾	30.93%⁽⁹³²⁾	23.74%^(114321)
Annual income ($)
0-20,000	38.27%⁽⁸⁴³⁾	52.10%^(19572)	33.18%⁽⁹²⁷⁾	43.25%^(212922)
20,001-35,000	22.47%⁽⁴⁹⁵⁾	23.55%⁽⁸⁸⁴⁷⁾	20.33%⁽⁵⁶⁸⁾	22.02%^(108411)
35,001-70,000	32.09%⁽⁷⁰⁷⁾	20.53% ⁽⁷⁷¹⁰⁾	32.93%⁽⁹²⁰⁾	25.49%^(125505)
70,001+	7.17%⁽¹⁵⁸⁾	3.82%⁽¹⁴³⁴⁾	13.56%⁽³⁷⁹⁾	9.24%^(45507)

Source: HWR wave 1 and 2006 Census.

Notes:

Sub-sample given in parentheses. These may vary from sample total due to missing data.
For the purposes of comparing with the Census, approximately 375 participants are excluded from the age-group analysis as they were 54 years old at the time of the wave 1 survey. This reflects the imprecision of the Electoral Roll's age-indicator which is based on participants' “birth year” rather than their specific birth-date. Four further participants were excluded from the age-group analysis, as they reported ages beyond the 70-year upper limit.
Secondary = high school; post secondary = trade or polytechnic; tertiary = university

The demographic characteristics of the cross-sectional baseline sample were compared with the HWR longitudinal sample characteristics at wave 2 and wave 3 (see Table 13).

These results suggest that the wave 2 sample is comprised of baseline participants who are more likely to be working, in better health, better educated and less likely to smoke, but more likely to consume alcohol. The transition from wave 2 to wave 3 highlighted an ethnicity-specific divergence in demographic hallmarks. Whereas Māori in wave 3 were more likely than attritors to be partnered, in better health, and non-smoking, the non-Māori in wave 3 were more likely than attritors to be female, educated, non-smokers and more frequent drinkers. These differences should be borne in mind when considering the results and conclusions of the analysis.

Table 13 – Changes in the characteristics of the HWR sample across waves using baseline data from 2006.
	Baseline (2006)	Wave 2 (2008)	Wave 3 (2010)
Total number	6,657	2,472	1,835
Māori	3,117	1065	707
Non-Māori	3,540	1407	1128
Mean age ^(SD)
Māori	60.79^(4.69)	61.00^(4.59)	61.16 ^(4.63)
Non-Māori	61.07^(4.69)	61.15^(4.48)	61.29 ^(4.50)
Females
Māori	55.88%⁽¹⁷³⁴⁾	56.17%⁽⁵⁹⁶⁾	54.69% ⁽³⁸⁵⁾
Non-Māori	52.99%⁽¹⁸⁰⁷⁾	51.31%⁽⁷⁰⁷⁾	52.67% ⁽⁵⁸¹⁾
Partnered (married/de facto)
Māori	63.97%⁽¹⁹⁸⁵⁾	65.60%⁽⁶⁹⁶⁾	68.14% ⁽⁴⁷⁹⁾
Non-Māori	76.56%⁽²⁶¹⁶⁾	76.56%⁽¹⁰⁵⁵⁾	77.54% ⁽⁸⁵⁶⁾
Working (full & part-time)
Māori	62.12%⁽¹⁷⁷⁹⁾	64.84%⁽⁶⁴⁹⁾	65.57% ⁽⁴³⁸⁾
Non-Māori	65.79%⁽²²²⁵⁾	69.40%⁽⁹⁴⁸⁾	68.97% ⁽⁷⁵⁸⁾
Lives in urban centre (30,000+)
Māori	42.46%⁽¹²⁸⁹⁾	43.40%⁽⁴⁵⁴⁾	43.62% ⁽³⁰⁴⁾
Non-Māori	52.38%⁽¹⁸⁰⁸⁾	51.26%⁽⁷¹⁴⁾	51.84% ⁽⁵⁷⁹⁾
% Current smoker
Māori	22.39%⁽⁶⁸³⁾	18.80%⁽¹⁹⁸⁾	16.50% ⁽¹¹⁵⁾
Non-Māori	12.95%⁽⁴⁵⁰⁾	11.33%⁽¹⁵⁸⁾	10.28% ⁽¹¹⁵⁾
Educational qualifications
Māori
No secondary	56.27%⁽¹⁵⁰⁸⁾	45.85%⁽⁴³¹⁾	45.24% ⁽²⁸⁵⁾
Secondary	9.59%⁽²⁵⁷⁾	10.11%⁽⁹⁵⁾	8.89% ⁽⁵⁶⁾
Post-secondary	12.09%⁽³²⁴⁾	14.57%⁽¹³⁷⁾	14.92% ⁽⁹⁴⁾
Tertiary	22.05%⁽⁵⁹¹⁾	29.47%⁽²⁷⁷⁾	30.95% ⁽¹⁹⁵⁾
Non-Māori
No secondary	38.12%⁽¹¹⁶⁰⁾	31.14%⁽³⁸³⁾	30.29% ⁽²⁹⁹⁾
Secondary	14.92%⁽⁴⁵⁴⁾	15.20%⁽¹⁸⁷⁾	14.49% ⁽¹⁴³⁾
Post-secondary	15.35%⁽⁴⁶⁷⁾	15.77%⁽¹⁹⁴⁾	15.40% ⁽¹⁵²⁾
Tertiary	31.61%⁽⁹⁶²⁾	37.89%⁽⁴⁶⁶⁾	39.82% ⁽³⁹³⁾
Economic living standard
Māori
Hardship	37.74%⁽⁶⁸⁵⁾	33.28%⁽²⁰⁷⁾	30.60% ⁽¹²³⁾
Comfortable	49.09%⁽⁸⁹¹⁾	50.16%⁽³¹²⁾	51.24% ⁽²⁰⁶⁾
Good	13.17%⁽²³⁹⁾	16.56%⁽¹⁰³⁾	18.16% ⁽⁷³⁾
Non-Māori
Hardship	20.53%⁽⁴⁰³⁾	18.50%⁽¹⁵¹⁾	17.78% ⁽¹¹⁷⁾
Comfortable	51.55%⁽¹⁰¹²⁾	53.92%⁽⁴⁴⁰⁾	53.50% ⁽³⁵²⁾
Good	27.92%⁽⁵⁴⁸⁾	27.57%⁽²²⁵⁾	28.72% ⁽¹⁸⁹⁾
Current health
Māori
Fair/poor	20.77%⁽⁶⁴⁰⁾	17.77%⁽¹⁸⁸⁾	15.63% ⁽¹¹⁰⁾
Good	34.21%⁽¹⁰⁵⁴⁾	31.47%⁽³³³⁾	31.25% ⁽²²⁰⁾
Very good/excellent	45.02%⁽¹³⁸⁷⁾	50.76%⁽⁵³⁷⁾	53.13% ⁽³⁷⁴⁾
Non-Māori
Fair/poor	12.28%⁽⁴³¹⁾	10.16%⁽¹⁴²⁾	9.45% ⁽¹⁰⁶⁾
Good	31.30%⁽¹⁰⁹⁹⁾	29.28%⁽⁴⁰⁹⁾	29.14% ⁽³²⁷⁾
Very good/excellent	56.42%⁽¹⁹⁸¹⁾	60.56%⁽⁸⁴⁶⁾	61.41% ⁽⁶⁸⁹⁾
Alcohol consumption
Māori
Never	26.78%⁽⁸²⁴⁾	22.37%⁽²³⁶⁾	20.86% ⁽¹⁴⁶⁾
Monthly or less	27.95%⁽⁸⁶⁰⁾	27.68%⁽²⁹²⁾	27.57% ⁽¹⁹³⁾
2-4 times per month	16.28%⁽⁵⁰¹⁾	17.06%⁽¹⁸⁰⁾	16.86% ⁽¹¹⁸⁾
2-3 times per week	14.53%⁽⁴⁴⁷⁾	16.02%⁽¹⁶⁹⁾	16.14% ⁽¹¹³⁾
4 or more times per week	14.46%⁽⁴⁴⁵⁾	16.87%⁽¹⁷⁸⁾	18.57% ⁽¹³⁰⁾
Non-Māori
Never	15.37%⁽⁵³⁹⁾	12.65%⁽¹⁷⁷⁾	11.41% ⁽¹²⁸⁾
Monthly or less	17.88%⁽⁶²⁷⁾	16.44%⁽²³⁰⁾	16.49% ⁽¹⁸⁵⁾
2-4 times per month	16.14%⁽⁵⁶⁶⁾	16.80%⁽²³⁵⁾	17.83% ⁽²⁰⁰⁾
2-3 times per week	20.87%⁽⁷³²⁾	21.16%⁽²⁹⁶⁾	21.39% ⁽²⁴⁰⁾
4 or more times per week	29.74%⁽¹⁰⁴³⁾	32.95%⁽⁴⁶¹⁾	32.89% ⁽³⁶⁹⁾

Notes

[13]The distinction between Māori and non-Māori in this table (and henceforth) reflects prioritised responses (see Statistics New Zealand, 2001) to HWR ethnicity questions rather than the Electoral Roll-based categorisation used for sample selection purposes.

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9 Appendix B

9.1 Representativeness at baseline and sample attrition

Sex

Age (year groups)

Marital status

Work status

Educational qualifications

Annual income ($)

Mean age ^(SD)

Females

Partnered (married/de facto)

Working (full & part-time)

Lives in urban centre (30,000+)

% Current smoker

Educational qualifications

Māori

Non-Māori

Economic living standard

Māori

Non-Māori

Current health

Māori

Non-Māori

Alcohol consumption

Māori

Non-Māori

Notes

Global Navigation

Personal tools

9 Appendix B

9.1 Representativeness at baseline and sample attrition

Sex

Age (year groups)

Marital status

Work status

Educational qualifications

Annual income ($)

Mean age (SD)

Females

Partnered (married/de facto)

Working (full & part-time)

Lives in urban centre (30,000+)

% Current smoker

Educational qualifications

Māori

Non-Māori

Economic living standard

Māori

Non-Māori

Current health

Māori

Non-Māori

Alcohol consumption

Māori

Non-Māori

Notes

Mean age ^(SD)