Thousands of households will keep a two-week record of daily expenditure in a year-long survey to determine spending patterns.

The National Statistics Office yesterday rolled out the Household Budgetary Survey, a €600,000 exercise that will register how families spend their money and what they earn.

The survey was last held in 2008 and the results of the forthcoming survey, expected at the end of next year, will shed light on new trends such as online shopping.

The survey will be used to update the retail price index, the tool that determines the statutory cost of living adjustment. It is also used for social and economic research and is important in the calculation of gross domestic product.

The Household Budgetary Survey will cost €600,000 and register what families earn

The NSO said the collection of data will start later this month when selected households will be asked to fill in a two-week diary of expenditure. The agency aims to reach 7,000 households over the next year.

Selected households will fill in a general questionnaire that will also include details of income and extraordinary expenses such as car purchases, which are unlikely to be captured in the diary. Households that participate in the survey will be given a compensation of €40 and all collected data will remain confidential.

The NSO said the families will be visited by a data collector but will be informed beforehand through the post.

Families can ascertain the identity of the data collector by phoning the NSO. All data collectors will carry identity tags.