SoFIE is New Zealand's first national survey designed to study income, family type and employment, and how these change over time. Interviewing for SoFIE began in October 2002. SoFIE is a longitudinal survey that Statistics New Zealand plans to run for eight waves (or interview cycles).
A longitudinal survey involves revisiting the same people or 'respondents' over time. This contrasts with a cross-sectional survey where different respondents are selected each time the survey is repeated. As a longitudinal survey, SoFIE will be able to build a dynamic picture, somewhat like a movie, of how individual and family circumstances and lifestyles change over time. A cross-sectional survey would only give a series of snapshots.
At wave one, 15,000 randomly-selected households were approached to take part in SoFIE. Our interviewers visited each of the addresses and asked for the names of every member of the household. Household members were then asked questions to see if they were eligible for the survey (for example the survey does not interview overseas visitors who intend to stay in New Zealand for less than 12 months).
All eligible household members who responded to this first wave of the survey became original survey members (OSMs). They will be asked to complete an interview for the eight waves of the survey, even if their household changes. Anyone who begins living with an OSM during the course of SoFIE will also be interviewed, but only for as long as they continue to live with an OSM.
At wave one, 15,000 randomly-selected households were approached to take part in SoFIE. Our interviewers visited each of the addresses and asked for the names of every member of the household. Household members were then asked questions to see if they were eligible for the survey (for example the survey does not interview overseas visitors who intend to stay in New Zealand for less than 12 months). All eligible household members who responded to this first wave of the survey became original survey members (OSMs). They will be asked to complete an interview for the eight waves of the survey, even if their household changes. Anyone who begins living with an OSM during the course of SoFIE will also be interviewed, but only for as long as they continue to live with an OSM.
The information SoFIE gathers will assist in the development of a range of economic and social policies. The survey results will help the government and New Zealanders understand the factors that have the most impact on social and economic wellbeing over time (factors like educational qualifications, family situation, sources of income, and age). The resulting statistics can be used to answer questions such as:
TheLongitudinal Immigration Survey: New Zealand is a partnership between the Department of Labour and Statistics New Zealand. In November 2001, Statistics NZ published a research report on analysing data from the Household Labour Force Survey in a longitudinal way, A Longitudinal Look at some Data of the Household Labour Force Survey.
top
Original sample members are interviewed once a year over an eight year period from 2002 to 2010. From the second interview onwards, people who remain living with OSMs are also interviewed once a year.
The entire interview takes about 40–50 minutes for each adult. For a child aged under 15 years, an adult answers on their behalf and the questions should only take one minute. An interviewer will arrange a convenient time to interview those members of your household who are aged 15 years and over. The interviewer is able to visit your household more than once, at your convenience, to ensure everyone completes an interview. The interviewer uses a laptop computer (with showcards for some answers) to record the answers.
Two questionnaires are used to collect information for SoFIE – the household questionnaire is answered by one person in each household and collects household characteristics. A personal questionnaire is completed with every original survey member aged 15 years and over. A slightly shorter version of the personal questionnaire is completed with any adult cohabiting with an original survey member adult from wave two onwards. Children aged under 15 years are not interviewed; instead, a nominated parent or other adult is asked questions about them.
The household questionnaire contains two modules of questions:
The personal questionnaire contains the following modules:
In wave two, four six and eight a module collecting type and value of assets and liabilities will be included. In waves three, five and seven a health module, collecting self-rated health status, incidence of chronic diseases, major health events, risk factors and health service use, will be included.
Access to the interview system is controlled by a password. All interview data on the laptop is automatically stored in a form that would be meaningless without authorised access.
Under the Statistics Act 1975 you must provide the information requested by Statistics New Zealand. In the households selected, everyone aged 15 years and over takes part in an interview. Your help is vital and appreciated because responses from all kinds of people helps give us an accurate picture of New Zealanders' income and employment patterns. Your answers are important because they represent others like you.
Your responses for the full eight years of the SoFIE are very important for the validity of the resulting statistics. If you move house, please email your new address to sofie@stats.govt.nz, or call us on 0800 104 744.
Providing information to Statistics New Zealand is a statutory obligation. There is no provision in the Statistics Act 1975 for people to be paid for providing information.
The Statistics Act 1975 states that:
Consequently, Statistics New Zealand does not share your information with other government agencies. Other government agencies can provide their information to Statistics New Zealand, but only for statistical purposes. Statistics New Zealand sometimes undertakes a statistical survey jointly with another government department or government agency. In all cases, respondents are informed that it is a joint collection. You may object to information being passed to the other party by Statistics New Zealand. Where this right is exercised, Statistics New Zealand withholds the information from the other party.
Only people authorised by the Statistics Act are allowed to see your individual information, and they must use it only for statistical purposes. Your information will be combined with information from other people to prepare summary statistics about groups. We make sure that no individual can ever be identified when the results are published. Individual details such as your name and address are not included in data used for analysis to ensure privacy.