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UNECE Workshop on Seasonal Adjustment 20 – 23 February 2012, Ankara, Turkey. Publishing Seasonally Adjusted Data. Anu Peltola Economic Statistics Section, UNECE. Overview. Presentation of growth rates Detecting turning points Statistical news releases Improving readability
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UNECE Workshop on Seasonal Adjustment 20 – 23 February 2012, Ankara, Turkey Publishing Seasonally Adjusted Data Anu Peltola Economic Statistics Section, UNECE
Overview • Presentation of growth rates • Detecting turning points • Statistical news releases • Improving readability • Extracts from statistical news • Availability of time series data • General recommendations for new releases – example for industrial production • User support
Presentation of Growth Rates • Without seasonal adjustment • Growth rate from the same period of the previous year, e.g. January 2012 to January 2011 • Not free from calendar effects & historical picture • Seasonal adjustment • Makes different periods comparable • Provides faster indications of changes • Choice of growth rates for statistical releases requires careful consideration • Use consistent terminology for growth rates
Re-designing Statistical News Releases According to the ESS Guidelines on Seasonal Adjustment: • Analyze the results of seasonal adjustment before publishing data • Ensure transparency to users • Assist users in making informed decisions • Facilitate easy access to time series data • Provide seasonally adjusted figures if seasonality is present
Challenges with Statistical Releases • Offer the relevant information in a concise form • Keep the message simple and understandable • Include comprehensive information for correct conclusions • Guidelines: Handbook on Data and Metadata Reporting and Presentation (OECD)
Recommendations for Releasing Time Series Data 1. When seasonality is present offer seasonally adjusted 2. Focus on adjusted - give access to the original 3.+4. At the minimum provide period-to-period growth rates on seasonally adjusted 5. Year-on-year changes based on raw data or calendar adjusted 8. Disseminate a non-technical explanation of seasonal adjustment 9. Provide information for assessment of reliability 10. Provide metadata to enable repeating adjustment
Content of Statistical Releases • When releasing data with seasonal influence • Recommended to include in the release: • Higher level aggregates + Main contributors to change • Period-to-period growth rates for the latest period • Year-on-year growth rate (from calendar adjusted or original data) • Main revisions to the previous release • Additional options: • Growth rates based on the three months sum or moving average – useful with volatile series • Change or the value in levels • Cumulative growth rates
Extracts from Statistical News – Sweden Increase in industrial production in July Industrial production increased by 2.8 percent in seasonally adjusted figures in July compared to June. Comparing July with the same month of the previous year, industrial production increased by 8.2 percent in working day adjusted figures. The production in the industry sub-sectors… ... when comparing the latest three month period, May-July, with the previous three month period… ... development was the strongest in the electrical equipment industry… The figures for July are preliminary. Since the previous publication the change in industrial production in June compared to May has been revised upwards by… www.scb.se/Pages/PressRelease____320267.aspx
Extracts from Statistical News – United Kingdom www.ons.gov.uk/ons/dcp171778_233168.pdf
Time Series • Seasonally adjusted data are at their most useful form in a time series format, provide: • Access to the complete series • Original and seasonally adjusted series in full length • Access to trend-cycle and calendar day adjusted series • Index numbers, in a time series form, enable comparison of different sectors of the economy or different regions or countries • To provide only the latest growth rate without any time series is not useful enough!
UNSD - Releasing Industrial Production Index • International Recommendations for the Index of Industrial Production (UNSD, 2010) • Data released as soon as possible noting the trade-off between timeliness and quality • Follow an advance release calendar and consistent release practices > policy! • Make data available to all users at the same time • Foster confidentiality of individual data • Provide contact details of relevant statisticians
User support • Bases on • Transparency of metadata • Availability of general explanations on the statistical methods applied and • Good design of statistical releases • Websites providing additional data and metadata for those interested • Availability of experts in statistics
Effective News Release According to the UNECE Making Data Meaningful Guide: • Tells a story about the data • Has relevance for the public • Catches the reader's attention quickly with a headline or image • Is easily understood, interesting and often entertaining • Encourages others, including the media, to use statistics appropriately to add impact to what they are communicating