Digital Commons Network^™

Rotation Patterns And Trend Estimation For Repeated Surveys Using Rotation Group Estimates, Craig Mclaren, David Steel

Professor David Steel

A general approach for constructing filters to produce trend estimates from a repeated survey is described. This approach accounts for the correlation structure induced by the rotation pattern used in the survey. Different filters are developed depending on whether the trend analysis is based on elementary estimates available for each rotation group or overall estimates obtained by combining the rotation group estimates. The properties of trend estimates obtained directly from the elementary estimates, those obtained from the simple average of the rotation group estimates and trend estimates obtained from the best linear unbiased estimates of the population characteristics of interest …

Ignoring A Level In A Multilevel Model: Evidence From Uk Census Data, Mark Tramner, David Steel

Professor David Steel

Because of the inherent multilevel nature of census data, it is often appropriate to use multilevel models to investigate relationships between census variables. For a local population, the data available from the census allow a three-level nested model to be assumed, with an individual level (level 1), an enumeration district (ED) level (level 2), and a ward level (level 3). The consequences of ignoring one of the three levels in this model are assessed here theoretically. Empirical results, based on 1991 UK Census data, are also provided, comparing the variance components estimated from the three-level model with analyses based on …

Efficiency Of Split Questionnaire Surveys, James Chipperfield, David Steel

Professor David Steel

No abstract provided.

The Impact Of Different Rotation Patterns On The Sampling Variance Of Seasonally Adjusted And Trend Estimates, Craig Mclaren, David Steel

Professor David Steel

Many economic and social time series are based on sample surveys which have complex sample designs. The sample design affects the properties of the time series. In particular, the overlap of the sample from period to period affects the variability of the time series of survey estimates, and the seasonally adjusted and trend estimates produced from them. The Census X11 and X11ARIMA packages are commonly used to produce seasonally adjusted estimates and can also be used to produce estimates of trend. This paper considers the implications of different overlap patterns on the sampling variance of seasonally adjusted and trend estimates …

The Case For Small Area Microdata, Mark Tranmer, A. Pickles, Ed Fieldhouse, M. Elliot, A. Dale, Mark Brown, D. Martin, David Steel, C. Gardiner

Professor David Steel

No abstract provided.

An Evaluation Of A Large-Scale Cati Household Survey Using Random Digit Dialling, Don Bennett, David Steel

Professor David Steel

omputer-assisted telephone interviewing and random digit dialling are increasingly being used to conduct household surveys in Australia. However, there is little published information concerning Australian experience with such surveys. In 1995 the Government Statistician's Office in Queensland conducted a household survey to study population migration using these techniques. The survey involved a sample of 110 000 telephone numbers resulting in 38 000 responding households. This article describes a computerized survey management system that was developed and which provided information concerning important operational and quality aspects of the survey.

Design And Estimation For Split Questionnaire Surveys, James O. Chipperfield, David G. Steel

Professor David Steel

When sampling from a finite population to estimate the means or totals of K population characteristics of interest, survey designs typically impose the constraint that information on all K characteristics (or data items) is collected from all units in the sample. Relaxing this constraint means that information on a subset of the K data items may be collected from any given unit in the sample. Such a design, called a split questionnaire design (SQD), has three advantages over the typical design: increased efficiency with which design objectives can be met, by allowing the number of sample units from which information …

Optimum Allocation Of Sample To Strata And Stages With Simple Additional Constraints, Robert Clark, David Steel

Professor David Steel

The optimum allocation of a sample to strata and stages in a stratified two-stage design for a simple cost function is well known. In practice there may be reasons to impose simple additional constraints. It is shown how the theory for optimum allocation can be generalized to account for such constraints. A simple way of assessing the effect that each constraint has on the efficiency of the sample design is developed. This general approach allows several additional constraints that are used in practice to be applied. Data from the 1996 redesign of the Australian Monthly Labour Force Survey are used …

Statistical Indicators For Local Government Areas: A Case Study Of The Shoalhaven Lga, 1997, Nell Stetner-Houweling, David Steel, Greg Pullen

Professor David Steel

Decision makers and planers need to have relevant and reliable information to give a picture of how different areas are developing economically and socially. However, there is a perceived lack of timely and easily accessible data at the Local Government Area (LGA) level. This study produced a statistical profile of the Shoalhaven (LGA) by developing a conceptual framework, which represents the key economic, social, and population characteristics of the LGA. The statistical data available from the Australian Bureau of Statistics (ABS) at the level of the LGA, was investigated and summarised. Other sources of information available to create a statistical …

Restricted Quasi-Score Estimating Functions For Sample Survey Data, Yan Lin, David Steel, Raymond Chambers

Professor David Steel

This paper applies the theory of the quasi-likelihood method to model-based inference for sample surveys. Currently, much of the theory related to sample surveys is based on the theory of maximum likelihood. The maximum likelihood approach is available only when the full probability structure of the survey data is known. However, this knowledge is rarely available in practice. Based on central limit theory, statisticians are often willing to accept the assumption that data have, say, a normal probability structure. However, such an assumption may not be reasonable in many situations in which sample surveys are used. We establish a framework …

Simple Methods For Ecological Inference In 2x2 Tables, Raymond Chambers, David Steel

Professor David Steel

This paper considers inference about the individual level relationship between two dichotomous variables based on aggregated data. It is known that such analyses suffer from 'ecological bias', caused by the lack of homogeneity of this relationship across the groups over which the aggregation occurs. Two new methods for overcoming this bias, one based on local smoothing and the other a simple semiparametric approach, are developed and evaluated. The local smoothing approach performs best when it is used with a covariate which accounts for some of the variation in the relationships across groups. The semiparametric approach performed well in our evaluation …

Voter Turnout In British South Asian Communities At The 2001 General Election, D. Cutts, Ed Fieldhouse, K. Purdam, David Steel, Mark Tranmer

Professor David Steel

No abstract provided.

Conditional And Unconditional Models In Model-Assisted Estimation Of Finite Population Totals, David Steel, Robert Clark

Professor David Steel

The well known Godambe-Joshi lower bound for the anticipated variance of design unbiased estimators of population totals treats the auxiliary variables as constants. We extend the result to models where these variables are random and show that the generalized difference estimator using the expected values conditional on all auxiliary values is optimal. This has several implications including the fact that collecting multiple survey variables does not reduce the lower bound.

Scales, Levels And Processes: Studying Spatial Patterns Of British Census Variables, David Manley, Robin Flowerdew, David Steel

Professor David Steel

No abstract provided.

Exploring A Relationship Between Aggregate And Individual Levels Spatial Data Through Semivariogram Models, Gandhi Pawitan, David Steel

Professor David Steel

No abstract provided.

Multivariate Random Effect Models With Complete And Incomplete Data, James Chipperfield, David Steel

Professor David Steel

No abstract provided.

Measuring And Analysing Homogeneity Of Geographical Areas For A Categorical Variable, David Steel, Mark Tranmer

Professor David Steel

Many Variables have within group homogeneity (similarity of values for the individual units that comprise the groups). Measures of within group homogeneity are useful for the sample design and statistical analysis of datasets for populations that contain groups, such as individuals in geographical areas. Homogeneity measures can easily be defined for continuous or dichotomous variables. Here we propose a homogeneity measure for a multi-category variable and show how this measure can be calculated without access to individual level data. We apply the measure to data from the UK census and show how this measure can be related to the homogeneity …

The Effect Of Different Rotation Patterns On The Revisions Of Trend Estimates, David G. Steel, Craig H. Mclaren

Professor David Steel

The X11 and X11ARIMA procedures are widely used to produce seasonally adjusted and trend estimates from time series obtained from sample surveys. The surveys are often based on designs in which there is sample overlap between different periods. The degree of overlap is determined by the pattern of inclusion of selected units over time, i.e., the rotation pattern. An important issue in analysing the series is that trend estimates at the end of the series are revised as estimates for recent periods are added. This article considers the effects of different rotation patterns on the mean squared error of the …

Person-Level And Household-Level Regression Estimation In Household Surveys, David G. Steel, Robert Graham Clark

Professor David Steel

A common class of survey designs involves selecting all people within selected households. Generalized regressionestimators can be calculated at either the person or household level. Implementing the estimator at the household level has the convenience of equal estimation weights for people within households. In this article the two approaches are compared theoretically and empirically for the case of simple random sampling of households and selection of all persons in each selected household. We find that the household level approach is theoretically more efficient in large samples and any empirical inefficiency in small samples is limited.

The Impact Of Complex Survey Design On Prevalence Estimates Of Intakes Of Food Groups In The Australian National Children’S Nutrition And Physical Activity Survey, Alexandra Burden, Yasmine Probst, David G. Steel, L. C. Tapsell

Professor David Steel

Objective: To assess the impact of the complex survey design used in the 2007 Australian National Children’s Nutrition and Physical Activity Survey (ANCNPAS) on prevalence estimates for intakes of groups of foods in the population of children. Design: The impacts on prevalence estimates were determined by calculating design effects for values for food group consumption. The implications of ignoring elements of the sample design including stratification, clustering and weighting were discussed. Setting: The 2007 ANCNPAS used a complex sample design involving stratification, a high degree of clustering and estimation weights. Subjects: Australian children aged 2-16 years. Results: Design effects ranging …

Updating The Dietadvice Website With New Australian Food Composition Data, Yasmine Probst, Holley-Anne Jones, Shannon Lin, S. Burden, David G. Steel, Linda C. Tapsell

Professor David Steel

DietAdvice is an Australian self-administered dietary assessment website initially developed in 2003- 2005. The website allows patients to enter their dietary information and dieticians to remotely access and interpret the data. DietAdvice is presently being updated with new Australian food composition data. This study aims to describe the update process for moving from 1995 to 2006 food composition data. The database for the website was developed using grouped food data from the NUTTAB 1995 database. All food groups were cross-matched with the food from the NUTTAB 2006 database using the food ID codes. Rules were applied to determine the suitability …

Contextual Effects In Modeling For Small Domains, Mohammad-Reza Namazi-Rad, David G. Steel

Professor David Steel

During last two decades, different Small Area Estimation (SAE) methods have been proposed to overcome the challenge of finding reliable small area estimates. This happens a lot that the required data for various research purposes are available at different levels. Based on availability of data, individual-level or aggregated-level models are implied in SAE. However, the estimated values for model parameters obtained from individual-level analysis can be different from the one obtained based on analysis of aggregate data. Generally, this is referred to as the ecological fallacy. This happens due to some substantial contextual or area-level effects in the covariates. To …

The 2003 Australian Breast Health Survey: Survey Design And Preliminary Results, Elmer V. Villanueva, Sandra C. Jones, Caroline Nehill, Simone K. Favelle, David G. Steel, Don Iverson, Helen Zorbas

Professor David Steel

The Breast Health Surveys, conducted by the National Breast Cancer Centre (NBCC) in 1996 and 2003, are designed to gain insight into the knowledge, attitudes and behaviours of a nationally representative sample of Australian women on issues relevant to breast cancer. In this article, we focus on major aspects of the design and present results on respondents' knowledge about mammographic screening. Methods: The 2003 BHS surveyed English-speaking Australian women aged 3069 without a history of breast cancer using computer-assisted telephone interviewing. Questions covered the following themes: knowledge and perceptions about incidence, mortality and risk; knowledge and behaviour regarding early detection, …

Contextual Effects In Modeling For Small Domain Estimation, Mohammad-Reza Namazi-Rad, David G. Steel

Professor David Steel

Many different Small Area Estimation (SAE) methods have been proposed to overcome the challenge of findingreliable estimates for small domains. Often, the required data for various research purposes are available at differentlevels of aggregation. Based on the available data, individual-level or aggregated-level models are used in SAE.However, parameter estimates obtained from individual and aggregated level analysis may be different, in practice.This may happen due to some substantial contextual or area-level effects in the covariates which may be misspecifiedin individual-level analysis. If small area models are going to be interpretable in practice, possible contextualeffects should be included. Ignoring these effects leads …

Understanding Ageing In Older Australians: The Contribution Of The Dynamic Analyses To Optimise Ageing (Dynopta) Project To The Evidence Base And Policy, Kaarin Anstey, Allison Blelak, Carole Birrell, Colette Browning, Richard Burns, Julie Byles, Kim Kiely, Binod Nepal, Lesley Ross, David Steel, Timothy Windsor

Professor David Steel

Aim:  To describe the Dynamic Analyses to Optimise Ageing (DYNOPTA) project and illustrate its contributions to understanding ageing through innovative methodology, and investigations on outcomes based on the project themes. DYNOPTA provides a platform and technical expertise that may be used to combine other national and international datasets. Methods:  The DYNOPTA project has pooled and harmonised data from nine Australian longitudinal studies to create the largest available longitudinal dataset (n= 50652) on ageing in Australia. Results:  A range of findings have resulted from the study to date, including methodological advances, prevalence rates of disease and disability, and mapping trajectories of …

Estimates Of Probable Dementia Prevalence From Population-Based Surveys Compared With Dementia Prevalence Estimates Based On Meta-Analyses, Kaarin J. Anstey, Richard A. Burns, Carole Birrell, David G. Steel, Kim M. Kiely, Mary A. Luszcz

Professor David Steel

Background: National data on dementia prevalence are not always available, yet it may be possible to obtain estimates from large surveys that include dementia screening instruments. In Australia, many of the dementia prevalence estimates are based on European data collected between 15 and 50 years ago. We derived populationbased estimates of probable dementia and possible cognitive impairment in Australian studies using the Mini-Mental State Examination (MMSE), and compared these to estimates of dementia prevalence from meta-analyses of European studies.

Methods: Data sources included a pooled dataset of Australian longitudinal studies (DYNOPTA), and two Australian Bureau of Statistics National …

Video-Recorded Usability Testing Of A Web-Based Self-Administered Dietary Assessment, Yasmine Probst, David Steel, Linda Tapsell

Professor David Steel

No abstract provided.

Inclusion Of Mobile Phone Numbers Into An Ongoing Population Health Survey In Australia Using An Overlapping Dual Frame: Description Of Methods, Call Outcomes And Acceptance By Staff And Respondents, Margo Barr, Jason J. Van Ritten, David Steel, Sarah V. Thackway

Professor David Steel

In Australia telephone surveys has been the method of choice for ongoing population health surveys. Although it was estimated in 2011 that 20% of the population were mobile phone only persons the inclusion of mobile only phone users into these existing landline population health surveys has not occurred. This paper is part of a project that is looking in detail at the inclusion of mobile phone numbers into an ongoing population health survey in Australia. This paper describes the methods used, the call outcomes and acceptance by the population, supervisors and interviewing staff.

Measuring And Analyzing The Within Group Homogeneity Of Multi-Category Variables, David Steel, Mark Tranmer

Professor David Steel

No abstract provided.

Unravelling Ecological Analysis, David Steel, Mark Tranmer, D Holt

Professor David Steel

No abstract provided.