Methodological Note: Construction Index ICC

ICC. Methodological Note

CONSTRUCTION INDEX (ICC) FOR THE BASQUE COUNTRY. Base 2015

The Construction Index of the Basque Country is an indicator of short-term trends that aims to measure the evolution of activity in the construction sector of the Basque Country and thus enhance the information offered via the economic accounts.

It is a sample survey of companies whose main activity comes under Section F of the CNAE-2009 (National Classification of Economic Activities), and that totally or partially carry out their activity in the Basque Country.

The sample is fixed in each base year change via an exhaustive sampling of larger companies and a random sampling stratified by employment for the rest of the companies that comprise the objective population of the study. The result is a panel that guarantees the representation of companies in terms of their activity (building and civil works) and employment strata (fewer than 20, 20-49. 50-99, 100 or more).

The panel sample of the ICC is not fixed as it can vary over time, in response to the different delistings that may occur for various reasons, also permitting new inclusions. It currently comprises 523 companies in the construction sector.

The Construction Index is a Laspeyres weighted index based on fixed weightings calculated with the data of the base year. These indices have the advantage of being easy to calculate and interpret. The weighting coefficients used in the 2015 base year index are those obtained from the 2015 Construction Statistics prepared by Eustat.

Given the interest in having a continuous time data series for use in calculating predictions as in the analysis of the historical evolution of the series, Eustat has linked the 2015 base year series with those of the previous 2010 base year. In order to obtain a homogenous 2015 base year series from the first quarter of 1989 on the basis of values observed in the year 2015 in both bases some matching coefficients are obtained that are applied to values prior to 2015.

IThe indices are published in both gross terms and corrected for calendar effects and deseasonalised. Eustat, following the recommendations of Eurostat, uses the software JDemetra+ for series processing and signal extraction.