Cigarette smoking behaviour 2013 Census (information about this variable and its quality)

##Where the data comes from

Cigarette smoking behaviour is derived from question 21 and question 22 on the individual form.

##How this data is classified

1 Regular smoker

2 Ex-smoker

3 Never smoked regularly

7 Response unidentifiable

9 Not stated

Regular smoker – Someone who actively smokes one or more manufactured or hand–rolled tobacco cigarettes per day.

Never smoked – Someone who never actively smoked manufactured or hand rolled tobacco cigarettes at all or never actively smoked one or more per day.

Ex-smoker – Someone who is not a regular smoker now but had been a regular smoker of one or more cigarettes in the past.

For further information about this classification, refer to the:

• 2013 Census data dictionary
• Statistical standard for cigarette smoking behaviour.

For background information on classifications and standards, refer to the Classifications and related statistical standards page.

##Subject population

The subject population for this variable is the census usually resident population aged 15 years and over.

The subject population is the people, families, households, or dwellings to whom the variable applies.

##Non-response and data that could not be classified

Non response

'Non-response' is when an individual gives no response at all to a census question that was relevant to them. The non-response rate is the percentage of the subject population that was coded to ‘Not stated’.

• Non-response rate for 2013: 6.7 percent, of which 4.9 percent were substitutes.
• Non-response rate for 2006: 5.2 percent, of which 3.4 percent were substitutes.
• Non-response rate for 1996: 7.2 percent, of which 3.1 percent were substitutes.

Not elsewhere included

Non-response and responses that could not be classified or did not provide the type of information asked for are usually grouped together and called 'Not elsewhere included'.

• 9.2 percent of the subject population was coded to 'Not elsewhere included' in 2013, compared with 8.6 percent in 2006 and 7.8 percent in 1996.

For more information on non-response and substitute records, refer to the 2013 Census data user guide.

##How this data is used

Data from this variable is used to:

• monitor changes in smoking prevalence among the adult population of New Zealand
• understand the profile of smokers, to better target at-risk groups in the community with future health education programmes
• evaluate the success of health education programmes
• monitor changes in smoking prevalence among high-risk groups in New Zealand
• examine the inter-relationships between smoking and other socioeconomic variables and how these change over time.

Data quality processes

All census data was checked thoroughly during processing and evaluation, to ensure that it met quality standards and is suitable for use. These quality checks included edits.

All data must meet minimum quality standards to make it suitable for use.

Quality level

A quality level is assigned to all census variables: foremost, defining, or supplementary.

Cigarette smoking behaviour is a supplementary variable. Supplementary variables do not fit in directly with the main purpose of a census, but are still important to certain groups. These variables are given third priority in terms of effort and resources.

Mode of collection impacts – online forms compared with paper forms

The online forms had built-in editing functionality that directed respondents to the appropriate questions and ensured that their responses were valid. As a result of this, data from online forms may be of higher overall quality than data from paper forms. The significance of this will depend on the particular type of analysis being done. There will always be a mode effect but this cannot be measured. Statistics NZ design and test to minimise the effects of mode for all questions.

There were differences between how the forms were completed online and on paper for this variable:

• The online form allowed only one response to be selected for each of the smoking questions. If a further response was selected, the response given previously disappeared. Multiple responses to these questions were possible when forms were completed on paper.
• If respondents marked 'Yes' to the smoke regularly question online, the next question, ever smoked regularly, was greyed out so the respondent could not answer it.
• On the online form, only people who were 15 years of age or older and gave a New Zealand address in question 5 were able to respond to the smoking questions. When forms were completed on paper it was possible for respondents under 15 years or overseas visitors to respond to these questions.

##Quality assessment of data and data quality issues for this variable

Overall quality assessment

Moderate: fit for use – with some data quality issues to be aware of, to High: fit for use – with minor data quality issues only. 2013 Census variable quality rating scale gives more detail.

Issues to note

• Non-response rate for 2013: 6.7 percent, of which 4.9 percent were substitutes.
• The increased proportion of substitute forms impacted on the non-response rate. When substitute forms were included, the non-response rate for 2013 was higher than 2006. When substitute forms were excluded, the non-response rate for 2013 was similar to 2006.

For more information on non-response and substitute records, refer to the 2013 Census data user guide.

##Comparing this data with previous census data

This data is fully comparable with data from the 2006 Census. Changes in the data over this time period can be interpreted as real changes because there have been no changes in the way the data has been collected, defined, and classified.

This data is highly comparable with the 1996 Census data. Changes in the data over this time period can generally be interpreted as real changes. There may be a small component of change over time that is due to minor changes in the collection, definition, or classification of the data.

Change in treatment of partial responses

Between 2006 and 1996 there was a difference in the way partial response was treated.

In 2006, the ‘Not stated’ category for Cigarette smoking behaviour only included respondents who did not answer either of the smoking questions – question 21 ('Do you smoke regularly') and question 22 ('Ever smoked regularly'). Partial responses (ie when only one of the questions was answered but both should have been answered) were classified as 'Response unidentifiable'.

In 1996, the ‘Not stated’ category also included partial non-response.

This change has resulted in a decrease in the non-response rate in 2006 and a corresponding increase in the response unidentifiable rate between 1996 and 2006.

In 2013 and 2006, the ‘Not stated’ category for Cigarette smoking behaviour only included respondents who did not answer either of the smoking questions – question 21 ('Do you smoke regularly') and question 22 ('Ever smoked regularly') . Partial responses (ie when only one of the questions was answered but both should have been answered) were classified as 'Response unidentifiable'.

In 1996, the ‘Not stated’ category also included partial non-response.

This change has resulted in a decrease in the non-response rate in 2006 and a corresponding increase in the response unidentifiable rate between 1996 and 2006.

##Comparing this data with data from other sources

Census is the only information source that provides comprehensive information for small areas and small populations. However alternative sources of information about this subject are available:

• Household Economic Survey (HES)
• New Zealand General Social Survey (NZGSS)
• Alcohol and tobacco available for consumption.

Data from these alternative sources may show differences from census data for several reasons. These could be due to differences in scope, coverage, non-response rates, data being collected at different periods of time, alternative sources being sample surveys and as such subject to sampling errors, or differences in question wordings and method of delivery (self-administered versus interviewer-administered). Data users are advised to familiarise themselves with the strengths and limitations of individual data sources before comparing with census data.

##Further information about this data

All percentages in census publications have been calculated using 'Total stated' as the denominator.

When using this data, be aware that:

• Cigarette smoking behaviour is a cyclical topic. It was first included in the 1976 Census, and repeated in the 1981, 1996, and 2006 Censuses.

Contact our Information Centre for further information about using this variable.