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The U.S. Third National Health and Nutrition Examination Survey (NHANES III) was carried out from 1988 to 1994. This survey was intended primarily to provide estimates of cross-sectional parameters believed to be approximately constant over the six-year data collection period. However, for some variable (e.g., serum lead, body mass index and smoking behavior), substantive considerations suggest the possible presence of nontrivial changes in level between 1988 and 1994. For these variables, NHANES III is potentially a valuable source of time-change information, compared to other studies involving more restricted populations and samples. Exploration of possible change over time is complicated by two issues. First, there was of practical concern because some variables displayed substantial regional differences in level. This was of practical concern because some variables displayed substantial regional differences in level. Second, nontrivial changes in level over time can lead to nontrivial biases in some customary NHANES III variance estimators. This paper considers these two problems and discusses some related implications for statistical policy.

The objective of this research project is to examine the long-term consequences of being raised in a single parent household. We examine the impact of parental separation or divorce on the adult labour market behaviour of children ten to fifteen years after the event. In particular, we relate the family income and household characteristics of a cohort of individuals who are 16 to 19 years of age in 1982 to their labour market earnings, reliance on social transfers (UI and Income Assistance), and marital/fertility outcomes during the early 1990s, when they are in their late 20s and early 30s. Our data is based upon the linked income tax records developed by us at Statistics Canada, the Survey of Labour and Income Dynamics, and the National Longitudinal Survey of Children and Youth.

Victimizations are not randomly scattered through the population, but tend to be concentrated in relatively few victims. Data from the U.S. National Crime Victimization Survey (NCVS), a multistage rotating panel survey, are employed to estimate the conditional probabilities of being a crime victim at time t given the victimization status in earlier interviews. Models are presented and fit to allow use of partial information from households that move in or out of the housing unit during the study period. The estimated probability of being a crime victim at interview t given the status at interview (t-l) is found to decrease with t. Possible implications for estimating cross-sectional victimization rates are discusssed.

A model of secondary school progression has been estimated using data from the 1991 School Leavers Survey conducted by Statistics Canada. The data on which the school progression model was based comprised current educational status and responses to retrospective questions on the timing of schooling events. These data were sufficient for approximate reconstruction of educational event histories of each respondent. The school progression model was designed to be included in a larger, continuous time micro-simulation model. Its main features involve estimation -- by age, month of birth and season for both sexes in each province -- of rates of graduation, of dropout, of return and of dropout graduation. Estimation was reinforced with auxiliary 1991 Census and administative data.

In a longitudinal survey conducted for k periods some units may be observed for less than k of the periods. Examples include, surveys designed with partially overlapping subsamples, a pure panel survey with nonresponse, and a panel survey supplemented with additional samples for some of the time periods. Estimators of the regression type are exhibited for such surveys. An application to special studies associated with the National Resources Inventory is discussed.

Multivariate logistic regression, introduced by Glonek and McCullagh (1995) as a generalisation of logistic regression, is useful in the analysis of longitudinal data as it allows for dependent repeated observations of a categorical variable and for incomplete response profiles. We show how the method can be extended to deal with data from complex surveys and we illustrate it on data from the Swiss Labour Force Survey. The effect of the sampling weights on the parameter estimates and their standard errors is considered.

For longitudinal data, mixed models are often used, since they allow analysts to take account of the correlation between different observations from the same individual. The finite mixture model may be considered as a special case of a mixed model. In this document, attention will be given to the maximum likelihood method. The maximization of the likelihood function for a finite mixture of distributions is generally more difficult than in the usual case of a single distribution and can require considerable time. The objective of this project was therefore primarily to identify the one or more algorithms that best meet the criteria of run time and of efficiency in finding the solution. To achieve this objective, a simulation study was carried out. Only the situation in which the dependent variable is dichotomous was considered. This situation is very useful in practice, since among other things it can be used to model discrete durations, such as the length of time in "low income" status.

The National Longitudinal Survey of Children (NLSC) is the first Canada-wide survey of children. Starting in 1994, it will gather information on a sample of children and their life experiences. It will follow these children over time, collecting information on the children and their families, education, health, development, behaviour, friends, activities, etc.

Heart disease and stroke are major causes of illness, disability and death in Canada and they exact high personal, community and health care costs. The goal of The changing face of heart disease and stroke in Canada, the fifth in a series of reports from the Canadian Heart and Stroke Surveillance System (CHSSS), is to provide health professionals and policy makers with an overview of current trends in risk factors, interventions and services, and health outcomes of heart disease and stroke in Canada.

These highlights provide a brief summary of the report "Inequalities in literacy skills among youth in Canada and the United States", the latest monograph released using data from the International Adult Literacy Survey. This report suggests that youth in North America do not fare as well in their literacy skills as their European counterparts. Variables such as income and education continue to have direct and indirect effects on people's literacy skills.

This document brings together data from a number of Statistics Canada surveys and provides a visual perspective on the following subject areas: crime, police administration, adult and youth court activity, the correctional population, costs of the criminal justice system, violence against women, Canadians' experiences with crime, and their perceptions and fears of crime.

This compendium of vital statistics includes summary data on births, deaths, marriages and divorces. The introduction covers the data sources, data quality, and methods pertaining to each event, and includes a glossary defining the terms used. The first chapter is a brief overview of vital statistics for 1996. Subsequent chapters treat marriage, divorce, birth, fetal and infant mortality, total mortality, causes of death, vital statistics by census division, and international comparisons. Most charts and tables show Canada data for 1986 though 1996, while the charts and tables for causes of death show Canada data for 1979 through1996. Data for the provinces and territories are usually shown for 1995 and 1996. Appendices include population denominator data, age-standardized mortality rate (ASMR) calculation methods, and leading causes of death methodology.

Operating ratios for top carriers improved by one point in the first and second quarter of 1999 over the same period one year earlier. Average revenue per carrier fell 1% in the first quarter and rose only 3% in the second quarter.

On an industry wide basis, Canadian bus companies continue to grow and prosper. Gross revenues in 1998 (excluding subsidies) were 8.6 percent higher than in 1995.

With the exception of the third quarter (0.94), for-hire motor carriers of freight posted seasonally adjusted operating ratios of 0.93 in three out of the four quarters of 1998.

Data on registration of motor vehicles by type including passenger automobiles, trucks, motorcycles, buses, trailers and others are presented in this publication. A historical table of total registrations is provided. Motor vehicle registrations are shown by census divisions and municipalities where available. Data definitions, analysis, the methodology employed, an explanation of data quality and a bibliography are included.

This on-line publication provides detailed capital expenditures by type of asset on both construction and machinery and equipment made by private and public organizations in Canada. For each province and territory and for the 19 divisions of the Canadian economy, it details capital expenditures according to four types of residential construction, 95 types of non-residential construction, and 56 categories of machinery and equipment. Included are data on capital expenditures for major renovation and alteration of construction assets as well as for major retrofit and refurbishing of machinery and equipment assets. Trade and general construction contractors, suppliers of construction materials, and suppliers of machinery and equipment will find these data useful for market analysis.

This monthly publication presents data by weight on the acquisition, stock, production and shipment of raw and refined sugar for the month and the year-to-date from refiners of raw cane or beet sugars as well as those who further process such sugars. Geographic detail is at the national level. The December issue includes a list of reporting firms.

Consulting Engineering Services Price Index (CEPI) is an annual index that measures changes in the prices for services provided by consulting engineers. These services encompass advisory and design work as well as construction or project management. They are provided for many types of projects (fields of specialization), and to both Canadian and foreign clients. Price indexes are published for 10 fields of specialization as well as for national, regional, and foreign markets.

This occasional on-line bulletin series presents price indexes published by the Goods and Services Producing Industries Section, Prices Division. Each issue will contain different service price indexes.

International tourism is one of the fastest-growing industries in the world. Over the past ten years, the number of international arrivals at national borders has increased at an average annual rate of 5.2%, reaching 611 million in 1997.

Canada's economy was booming in 1997. The economy, as measured by the Gross Domestic Product (GDP), grew 3.8% in 1997, its best performance since 1994 and the second best this decade.

Canada hosted over 45 million international visitors in 1997, the highest annual level in the 25 years that travel data have been collected.

Vast distances, dependence on trade and low population density (compared to the United States and Europe) make transportation vitally important in Canada. The nation's travel and tourism patterns, both domestically and internationally, are a mirror image of Canadian business, lifestyles and quality of life.

This chapter describes four specific industry sectors : accomodation services, restaurant services, travel agencies and tour operators, and Canadian tourist attractions.

Tourism affects a number of industries. Hotels, travel agencies, airlines and restaurants are to varying degrees affected by tourism. Thus, tourism is not just one industry, but an amalgam of several, and the tourism phenomenon raises a number of questions because of its complexity, its various ramifications and its scope.

This article provides a thumbnail sketch of the top ten tourism regions in Canada based on the number of overnight visits. It will point out some of the similarities these regions share, as well as what makes them unique.

The purpose of this study was to describe tourism patterns in terms of the regions from which toursits orginate, and to identify those demographic and behavioural factors associated with the tourists generated by those regions.

The purpose of this chapter is, first, to review some of the current long and medium term forecasts for tourism globally and within Canada. Secondly, the chapter discusses some of the Canadian tourism industries' current responses to their changing economic and social context.

The Province of Ontario has traditionally been divided into 12 travel regions known as OTAPs (Ontario Travel Association Partners). Core funding for these OTAPs comes form the Ministry of Economic Development.

At the end of 1993, Eurostat lauched a 'community' panel of households. The first wave, carried out in 1994 in the 12 countries of the European Union, included some 7,300 households in France, and at least 14,000 adults 17 years or over. Each individual was then followed up and interviewed each year, even if they had moved. The individuals leaving the sample present a particular profile. In the first part, we present a sketch of how our sample evolves and an analysis of the main characteristics of the non-respondents. We then propose 2 models to correct for non-response per homogeneous category. We then describe the longitudinal weight distribution obtained from the two models, and the cross-sectional weights using the weight share method. Finally, we compare some indicators calculated using both weighting methods.

The U.S. Bureau of the Census implemented major changes to the design of the Survey of Income and Program Participation (SIPP) with the panel begun in 1996. The revised survey design emphasized longitudinal applications and the Census Bureau attempted to understand and resolve the seam bias common to longitudinal surveys. In addition to the substantive and administrative redesign of the survey, the Census Bureau is improving the data processing procedures which yield microdata files for the public to analyse. The wave-by-wave data products are being edited and imputed with a longitudinal element rather than cross-sectionally, carrying forward information from a prior wave that is missing in the current wave. The longitudinal data products will be enhanced, both by the redesigned survey and new processing procedures. Simple methods of imputing data over time are being replaced with more sophisticated methods that do not attenuate seam bias. The longitudinal sample is expanding to include more observations which were nonrespondents in one or more waves. Longitudinal weights will be applied to the file to support person-based longitudinal analysis for calendar years or longer periods of time (up to four years).

This article extends and further develops the method proposed by Pfeffermann, Skinner and Humphreys (1998) for the estimation of gross flows in the presence of classification errors. The main feature of that method is the use of auxiliary information at the individual level which circumvents the need for validation data for estimating the misclassification rates. The new developments in this article are the establishment of conditions for model identification, a study of the properties of a model goodness of fit statistic and modifications to the sample likelihood to account for missing data and informative sampling. The new developments are illustrated by a small Monte-Carlo simulation study.

The study of social mobility, between labour market statuses or between income levels, for example, is often based on the analysis of mobility matrices. When comparing these transition matrices, with a view to evaluating behavioural changes, one often forgets that the data derive from a sample survey and are therefore affected by sampling variances. Similarly, it is assumed that the responses collected correspond to the ' true value.'

A longitudinal study on a cohort of pupils in the secondary school has been conducted in an Italian region since 1986 in order to study the transition from school to working life. The information have been collected at every sweep by a mail questionnaire and, at the final sweep, by a face-to-face interview, where retrospective questions referring back to the whole observation period have been asked. The gross flows between different discrete states - still in the school system, in the labour force without a job, in the labour force with a job - may then be estimated both from prospective and retrospective data, and the recall effect may be evaluated. Moreover, the conditions observed by the two different techniques may be regarded as two indicators of the 'true' unobservable condition, thus leading to the specification and estimation of a latent class model. In this framework, a Markov chain hypothesis may be introduced and evaluated in order to estimate the transition probabilities between the states, once they are corrected or the classification errors. Since the information collected by mail show a given amount of missing data in terms of unit nonresponse, the 'missing' category is also introduced in the model specification.

The log-linear modelling of categorical longitudinal survey data on income is studied. An emphasis is on inference about change. Special attention is paid to modelling of longitudinal data from two waves. A small illustration is based on data from the Canadian Survey of Labour and Income Dynamics.

The purpose of the present study is to utilize panel data from the Current Population Survey (CPS) to examine the effects of unit nonresponse. Because most nonrespondents to the CPS are respondents during at least one month-in-sample, data from other months can be used to compare the characteristics of complete respondents and panel nonrespondents and to evaluate nonresponse adjustment procedures. In the current paper we present analyses utilizing CPS panel data to illustrate the effects of unit nonresponse. After adjusting for nonresponse, additional comparisons are also made to evaluate the effects of nonresponse adjustment. The implications of the findings and suggestions for further research are discussed.

The disseminated results of annual business surveys inevitably contain statistics that are changing. Since the economic sphere is increasingly dynamic, a simple difference of aggregates between n-l and n is no longer sufficient to provide an overall description of what has happened. The change calculation module in the new generation of annual business surveys divides overall change into various components (births, deaths, inter-industry migration) and calculates change on the basis of a constant field, assigning special importance to restructurings. The main difficulties lie in establishing subsamples, reweighting, calibrating according to calculable changes, and taking account of restructuring.

We address the problem of estimation for the income dynamics statistics calculated from complex longitudinal surveys. In addition, we compare two design-based estimators of longitudinal proportions and transition rates in terms of variability under large attrition rates. One estimator is based on the cross-sectional samples for the estimation of the income class boundaries at each time period and on the longitudinal sample for the estimation of the longitudinal counts; the other estimator is entirely based on the longitudinal sample, both for the estimation of the class boundaries and the longitudinal counts. We develop Taylor linearization-type variance estimators for both the longitudinal and the mixed estimator under the assumption of no change in the population, and for the mixed estimator when there is change.

In longitudinal surveys, sample subjects are observed over several time points. This feature typically leads to dependent observations on the same subject, in addition to the customary correlations across subjects induced by the sample design. Much research in the literature has focussed on modeling the marginal mean of a response as a function of covariates. Liang and Zeger (1986) used generalized estimating equations (GEE), requiring only correct specification of the marginal mean, and obtained standard errors of regression parameter estimates and associated Wald tests, assuming a "working" correlation structure for the repeated measurements on a sample subject. Rotnitzky and Jewell (1990) developed quasi-score tests and Rao-Scott adjustments to "working" quasi-score tests under marginal models. These methods are asymptotically robust to misspecification of the within-subject correlation structure, but assume independence of sample subjects which is not satisfied for complex longitudinal survey data based on stratified multi-stage sampling. We proposed asymptotically valid Wald and quasi-score tests for longitudinal survey data, using the Taylor Linearization and jackknife methods. Alternative tests, based on Rao-Scott adjustments to naive tests that ignore survey design features and on Bonferroni-t, are also developed. These tests are particularly useful when the effective degrees of freedom, usually taken as the total number of sample primary units (clusters) minus the number of strata, is small.