Kaikōura township quarterly time series

Standardising the GST reference period to quarterly Inland Revenue collects GST data as part of administering New Zealand’s taxation system. It is not primarily designed to produce economic statistics. We have developed methods to transform the GST data, which can be submitted monthly, two-monthly, or six-monthly; to a quarterly frequency. Sales for monthly returns are added together to get their quarterly sales. For two-monthly and six-monthly GST filers, some modelling and forward-casting is required to estimate a quarterly value. Example 1 – For a business that files GST two-monthly, we may need to estimate their quarterly sales based on just two months data. To do this, we apply a modelling factor to their two-monthly sales, to estimate their quarterly sales. Example 2 – For a business that files GST six-monthly, we may need to estimate their quarterly sales without any data from the period of interest. In this case, we disaggregate their sales into three two-monthly portions, and then apply a forward-casting factor to estimate their most recent sales. We then convert this two-monthly estimate into a quarterly estimate, as above. Accounting for GST groups Where one business reports GST on behalf of a number of other businesses that are linked by ownership (GST groups), the GST data must be apportioned between these different businesses. For GST groups, data from the Inland Revenue’s employer monthly schedule is used as follows: simple groups (where one group member has more than 80 percent of the group’s employees) – all sales are assigned to the dominant group member complex groups (where each individual group member has less than 80 percent of the group’s employees) – GST sales are apportioned between group members in proportion with their share of the group's employees. Data quality The GST data includes sales of goods and services together with other income such as sales of capital items and businesses, and potentially insurance payouts resulting from the earthquakes ( see insurance and depreciation). Only large capital items that could be identified at an aggregate level have been removed from the series. Seasonal adjustment We produce the seasonally adjusted and trend series using the X-13-ARIMA-SEATS package developed by the U.S. Census Bureau, to comply with international best practice. Seasonal adjustment aims to eliminate the impact of regular seasonal events (such as annual cycles in agricultural production, winter, or annual holidays) on time series. This makes the data for adjacent quarters more comparable. en-NZ