title: Non-response in the context of the New Zealand Census

authors: Pawar, Shefali Shashikant

subjects: Demography

abstract: The New Zealand Census provides an invaluable source of information on the estimated resident population of the country and its demographic, social and economic characteristics. The data derived from the census finds wide usage in research and analyses which inform numerous government policy decisions, including resource and funding allocation. Consequently, missing data caused by non-response to the census, whether unit (not returning completed census forms) or item (not providing a valid response to questions in the census forms) can cause a range of practical, methodological and ethical issues. Users of census datasets need to understand the implications of including or excluding the non-responding sub-population from their analyses.

This study looked at the residual non-response category ‘Not Stated’ or ‘Not Elsewhere Included’ (NS/NEI) for the 2006 and 2013 Censuses. NS/NEI is an aggregate of two different population groups. The majority are substitute records created by Statistics New Zealand as an estimate of the population not responding to the census at all, and the remaining are people who did not provide a valid response to the question on the census form, the item non-respondents. Detailed analyses were conducted on the variable that has one of the highest rates of item non-response: the question on personal income. The aim was to examine the demographic and socio-economic characteristics of the non-respondents and therefore identify any patterns or over-representation of certain population groups, likely to have an impact on any analysis carried out using these data.  This study therefore enables analysts to have a more evidence based approach towards dealing with this residual category.

The analysis of the demographic and available key socio-economic characteristics of the item non-respondents (NS/NEI group excluding substitutes) to the income question showed patterned behavior with certain population groups over-represented - females, youth, those aged 65+ years, Pacific Islanders and Māori, people born overseas, people receiving government benefits, those not in the labour force or unemployed and people working as labourers and machinery operators and drivers. Consequently, the exclusion or inclusion (by say, pro-rata apportioning or imputation) of the NS/NEI count from the analysis of the income variable will adversely affect these groups in terms of representativeness.

The users of census data need to take into account that the NS/NEI is not a homogeneous grouping. The imputed age-sex and spatial distribution of the majority of the substitutes is modelled on the population enumerated on census night and consequently, the demographic profile of the substitutes is more representative of census respondents. The substitutes included in the NS/NEI category can therefore substantially alter the demographic profile of the actual item non-respondents. To achieve an accurate profile, it is important to first exclude the substitutes from analyses. Decisions around the inclusion or exclusion of the NS/NEI count from any analysis can then be taken by ascertaining whether any particular population groups are over-represented among the item non-respondents and how the exclusion is likely to impact on the conclusion(s) reached from the analysis of that particular variable. Alternatively, for inclusion in the analysis, this will provide a more informed base for modelling the probable responses for the item non-respondents.

text: Non-response in the context of the New Zealand Census The New Zealand Census provides an invaluable source of information on the estimated resident population of the country and its demographic, social and economic characteristics. The data derived from the census finds wide usage in research and analyses which inform numerous government policy decisions, including resource and funding allocation. Consequently, missing data caused by non-response to the census, whether unit (not returning completed census forms) or item (not providing a valid response to questions in the census forms) can cause a range of practical, methodological and ethical issues. Users of census datasets need to understand the implications of including or excluding the non-responding sub-population from their analyses.

This study looked at the residual non-response category ‘Not Stated’ or ‘Not Elsewhere Included’ (NS/NEI) for the 2006 and 2013 Censuses. NS/NEI is an aggregate of two different population groups. The majority are substitute records created by Statistics New Zealand as an estimate of the population not responding to the census at all, and the remaining are people who did not provide a valid response to the question on the census form, the item non-respondents. Detailed analyses were conducted on the variable that has one of the highest rates of item non-response: the question on personal income. The aim was to examine the demographic and socio-economic characteristics of the non-respondents and therefore identify any patterns or over-representation of certain population groups, likely to have an impact on any analysis carried out using these data.  This study therefore enables analysts to have a more evidence based approach towards dealing with this residual category.

The analysis of the demographic and available key socio-economic characteristics of the item non-respondents (NS/NEI group excluding substitutes) to the income question showed patterned behavior with certain population groups over-represented - females, youth, those aged 65+ years, Pacific Islanders and Māori, people born overseas, people receiving government benefits, those not in the labour force or unemployed and people working as labourers and machinery operators and drivers. Consequently, the exclusion or inclusion (by say, pro-rata apportioning or imputation) of the NS/NEI count from the analysis of the income variable will adversely affect these groups in terms of representativeness.

The users of census data need to take into account that the NS/NEI is not a homogeneous grouping. The imputed age-sex and spatial distribution of the majority of the substitutes is modelled on the population enumerated on census night and consequently, the demographic profile of the substitutes is more representative of census respondents. The substitutes included in the NS/NEI category can therefore substantially alter the demographic profile of the actual item non-respondents. To achieve an accurate profile, it is important to first exclude the substitutes from analyses. Decisions around the inclusion or exclusion of the NS/NEI count from any analysis can then be taken by ascertaining whether any particular population groups are over-represented among the item non-respondents and how the exclusion is likely to impact on the conclusion(s) reached from the analysis of that particular variable. Alternatively, for inclusion in the analysis, this will provide a more informed base for modelling the probable responses for the item non-respondents.

year: 2016

title: Towards a new evolutionary subsampling technique for heuristic optimisation of load disaggregators

authors: Mayo, Michael

subjects: computer science

abstract: In this paper we present some preliminary work towards the development of a new evolutionary subsampling technique for solving the non-intrusive load monitoring (NILM) problem. The NILM problem concerns using predictive algorithms to analyse whole-house energy usage measurements, so that individual appliance energy usages can be disaggregated. The motivation is to educate home owners about their energy usage. However, by their very nature, the datasets used in this research are massively imbalanced in their target value distributions. Consequently standard machine learning techniques, which often rely on optimising for root mean squared error (RMSE), typically fail. We therefore propose the target-weighted RMSE (TW-RMSE) metric as an alternative fitness function for optimising load disaggregators, and show in a simple initial study in which random search is utilised that TW-RMSE is a metric that can be optimised, and therefore has the potential to be included in a larger evolutionary subsampling-based solution to this problem.

text: Towards a new evolutionary subsampling technique for heuristic optimisation of load disaggregators In this paper we present some preliminary work towards the development of a new evolutionary subsampling technique for solving the non-intrusive load monitoring (NILM) problem. The NILM problem concerns using predictive algorithms to analyse whole-house energy usage measurements, so that individual appliance energy usages can be disaggregated. The motivation is to educate home owners about their energy usage. However, by their very nature, the datasets used in this research are massively imbalanced in their target value distributions. Consequently standard machine learning techniques, which often rely on optimising for root mean squared error (RMSE), typically fail. We therefore propose the target-weighted RMSE (TW-RMSE) metric as an alternative fitness function for optimising load disaggregators, and show in a simple initial study in which random search is utilised that TW-RMSE is a metric that can be optimised, and therefore has the potential to be included in a larger evolutionary subsampling-based solution to this problem.

year: 2016

title: 'Entitled to a History': The World of Alice Tawhai's Short Stories and the Maori Literary Tradition

authors: Modlik, Kimberley

subjects: Alice Tawhai

abstract: New Zealand short story writer Alice Tawhai is one of the latest additions to the Maori literary tradition. Her three collections of short stories, Festival of Miracles, Luminous and Dark Jelly, deal with issues not entirely unique to New Zealand – from gang life, to domestic violence, to drug and alcohol abuse – and take as their primary subject an alienated, marginalized and disenfranchised underclass. This means she is likely to be read as speaking solely for the Maori experience.  This thesis will revise this misconception, which in effect ghettoizes or marginalizes Tawhai’s work.

Influential women writers of the Maori literary tradition, such as J. C. Sturm, Patricia Grace and Keri Hulme, have taken a particular interest in the long legacy of colonialism in New Zealand, especially of the impact of that legacy on Maori women. This thesis demonstrates that while Tawhai’s work engages with these familiar notions, her gaze is not limited to these issues. This thesis therefore places Tawhai’s work within that tradition and matrilineal genealogy before going on to show how she moves the paradigm beyond the usual grievances of biculturalism and colonialism, orienting her work instead around the increasingly multicultural experience of contemporary life in New Zealand.

The first section of this thesis will establish a platform for reading Tawhai in regards to her literary legacy and in the context of contemporary thinking, drawing on cultural theorist Stuart Hall and his theory on identity formation and identity politics as well as indigenous writings experts Patrick Evans and Chadwick Allen. This thesis will then move into its second section, which is an analysis of some of the overarching themes that can be found in the short stories of Tawhai’s literary foremothers, Sturm, Grace and Hulme. These include, for example, racism and discrimination, loss of ancestral lands, problems to do with urbanization and family violence.

The third and final section of this thesis will then consider Tawhai’s representation of contemporary experience, taking a particular interest in her portrayals of contemporary multicultural ethnic identities as well as the flexible and provisional nature of gendered and sexual identities today. The final subsection will then analyze her representations of the new family and social structures that may have replaced the traditional family model.

Through a close reading of her short stories and an appreciation of the legacy that she bears, this thesis will show how Tawhai’s work is a larger lens of contemporary New Zealand society as well as a significant addition to the Maori literary tradition.

text: 'Entitled to a History': The World of Alice Tawhai's Short Stories and the Maori Literary Tradition New Zealand short story writer Alice Tawhai is one of the latest additions to the Maori literary tradition. Her three collections of short stories, Festival of Miracles, Luminous and Dark Jelly, deal with issues not entirely unique to New Zealand – from gang life, to domestic violence, to drug and alcohol abuse – and take as their primary subject an alienated, marginalized and disenfranchised underclass. This means she is likely to be read as speaking solely for the Maori experience.  This thesis will revise this misconception, which in effect ghettoizes or marginalizes Tawhai’s work.

Influential women writers of the Maori literary tradition, such as J. C. Sturm, Patricia Grace and Keri Hulme, have taken a particular interest in the long legacy of colonialism in New Zealand, especially of the impact of that legacy on Maori women. This thesis demonstrates that while Tawhai’s work engages with these familiar notions, her gaze is not limited to these issues. This thesis therefore places Tawhai’s work within that tradition and matrilineal genealogy before going on to show how she moves the paradigm beyond the usual grievances of biculturalism and colonialism, orienting her work instead around the increasingly multicultural experience of contemporary life in New Zealand.

The first section of this thesis will establish a platform for reading Tawhai in regards to her literary legacy and in the context of contemporary thinking, drawing on cultural theorist Stuart Hall and his theory on identity formation and identity politics as well as indigenous writings experts Patrick Evans and Chadwick Allen. This thesis will then move into its second section, which is an analysis of some of the overarching themes that can be found in the short stories of Tawhai’s literary foremothers, Sturm, Grace and Hulme. These include, for example, racism and discrimination, loss of ancestral lands, problems to do with urbanization and family violence.

The third and final section of this thesis will then consider Tawhai’s representation of contemporary experience, taking a particular interest in her portrayals of contemporary multicultural ethnic identities as well as the flexible and provisional nature of gendered and sexual identities today. The final subsection will then analyze her representations of the new family and social structures that may have replaced the traditional family model.

Through a close reading of her short stories and an appreciation of the legacy that she bears, this thesis will show how Tawhai’s work is a larger lens of contemporary New Zealand society as well as a significant addition to the Maori literary tradition.

year: 2014