Chain Linking and Annual Update of Weights for Producer Price Indices for Services in Italy

Transcription

1 Chain Linking and Annual Update of Weights for Producer Price Indices for Services in Ital Cristina Cecconi, Francesco Santangelo, Adele Vendetti 29 th Voorburg Group Meeting Dublin, Ireland September 22 th - 26 th, 2014

2 Contents 1. Main features of the Italian SPPIs 2. SPPIs annual updating process 3. Chain linking vs fixed base approach: an example 2/10

3 Main features of the Italian SPPIs annuall chain-linked Lasperes tpe (ear ) chaining method: quarterl overlap base period: fourth quarter of ear weights reference period: ear reference period: ear 2010 annual updating basket, sample of units, weights calculation weighted means of level indices quarterl indices data collection, calculation, dissemination industr based enterprise price indices 3/10

4 SPPIs annual updating process SPPI ANNUAL UPDATING ear Basket of services Sample of units Weights Items selection Nace sub-sectors weights calculation TIME LINE Jul. Aug. Sep. Oct. Nov. Dec. Jan. Feb. Mar. Apr. Ma Jun. Services identification Sample selection Units involvement Units weights calculation 4/10

5 SPPIs annual updating process SPPI ANNUAL UPDATING ear Surve beginning for ear Basket of services Sample units Weights Collected items are observed and evaluated Sources: surve and statisticians Items selection TIME LINE Jul. Aug. Sep. Oct. Nov. Dec. Jan. Feb. Mar. Apr. Ma Jun. Services identification The list of services in the basket changes (new services in, and old services out), due to new knowledge or to technical changes Sources: sector studies, enterprises, knowledge in the field, etc. 5/10

6 SPPIs annual updating process SPPI ANNUAL UPDATING ear Surve beginning for ear Basket of services Sample of units Weights Enterprises in the sample receive Istat official communication for the surve Units involvement TIME LINE Jul. Aug. Sep. Oct. Nov. Dec. Jan. Feb. Mar. Apr. Ma Jun. Sample selection Units (enterprises) are selected in order to define the new sample Sources: Istat enterprises data base; sector s analsis 6/10

7 Basket of services SPPIs annual updating process SPPI ANNUAL UPDATING ear Sample of units Weights Surve beginning for ear Nace 3 digit weights (ear -3 or -2) are updated to the fourth quarter of ear, b using price changes Sources: Istat enterprises data base and external sources Nace sub-sectors weights calculation TIME LINE Jul. Aug. Sep. Oct. Nov. Dec. Jan. Feb. Mar. Apr. Ma Jun. Units weights calculation BtoB enterprise turnover and services BtoB turnover collected b the surve (ear -1) Sources: surve 7/10

8 Chain linking vs fixed base approach: an example Index Chain-linked index Fixed base index Mixed index Base period Reference period Weights reference period quarter 4, ear 2006=100 ear average of ear = average of ear =100 ear same sample of units chain-linked index: base period + weights reference period change earl fixed base index: base period + weights reference period agree with the reference period mixed index: base period coincides with the reference one and weights reference period changes earl 8/10

9 Chain linking vs fixed base approach: an example 9/10

10 Thank ou! Cristina Cecconi 10/10