How are the interviewees selected?

Interviewing all Finns would be very expensive and difficult. Therefore, the basis of our data collections is a sample drawn from a population, such as the database on the population of Finland.

Probability-based rules have been determined for forming the sample. The random sample thus formed enables generalisation of the results sufficiently accurately to the population and measuring of the uncertainty caused by the sample. Because each person drawn to the sample represents several persons, it is important that we receive data from as many persons drawn to the sample as possible. You cannot register for the sample. Statistics Finland always contacts the persons or enterprises selected to the sample in advance either by letter or email.

The sampling methods used by us are based on statistical science and thus they ensure reliable results, saves costs, help collect more detailed data on the survey topic and enable faster production of the results.

How do we try to contact respondents?

In Statistics Finland's data collections directed to persons or households, the respondent is a person selected to the sample, from whom responses to the questions of the data collection concerned are sought primarily.

When for some reason Statistics Finland is unable to contact the respondent, we try to reach the respondent through a person belonging to his or her household. When trying to reach the respondent we may be in contact with a person aged at least 18 for whom the same address of residence has been recorded in the Population Information System as for the respondent. We can also try to contact the respondent through other adult persons living at the same address.  

We try to contact the respondent through a person living at the same address if:

• The respondent does not have a functioning telephone number
• The respondent cannot be reached by telephone at the first two attempts
• An interview or call has been agreed with the respondent, but he or she cannot be reached

 

To ensure the privacy of respondents, the following principles are followed in interview work for contacting through another person. We try to reach the respondent through a person living at the same address:

• To reasonable extent, with respect to the duration of data collection and attempts to reach the respondent
• From telephone numbers listed in number search services or from numbers found from other commonly used sources
• Using the personal telephone number, email address or other personal contact information
• Primarily by telephone – after the attempt the respondent can be informed by a text message or answerphone message on what matter we have tried to reach him or her.

Attempts are made to reach persons living at the same address according to the time when the sample of the data collection was drawn from Statistics Finland’s population database. In all cases the persons are no longer necessarily registered at the same address in the interview situation.