Nordbotten and Denmark Lars Thygesen lth@dst.dk Danish statistics reform registers, new and unforeseen needs Nordbotten Poul Jensen

The impact of Nordbotten on statistical thinking in Denmark 1960 1966 1964 Nordbotten in Nordic Statistical Meeting Helsingfors Nordbotten in Nordic Chief Statisticians Meeting Copenhagen Ohlsson in Nordic Statistical Meeting Copenhagen Nordic cooperation inspiration EDP change cost structure micro data archives reuse data linkage Until then: One or a few prinicpal uses. Tables Future: Collect data continuously, use when needed 9/22/2018

Ingvar Ohlsson lectures, Copenhagen 1964 9/22/2018

Poul Jensen Aage la Cour Kjeld Bjerke Henning Friis Erling Jørgensen Axel Holm 9/22/2018

Milestones Kampmann, last Census Skak-Nielsen Act: Access to adm + influence on them 9/22/2018

Milestones #2 1976: -link to work places, - housing, education, occupation 9/22/2018

The basic ideas of Nordbotten – how they were implemented Value of capital in stock link 9/22/2018

The notion of a Statistical Information System CPR BDR CBR Educa- tion Employ- ment Person id: Person Number Enterprise CBR-No Dwelling Address Tax Inter- view Social Question- naire Health etc Cadastre 9/22/2018

Reuse of data for multiple purposes The Sample Archive from 1971 (originally the Mini Population Register) a representative sample of the population from a variety of sources and all kinds of social and population statistics longitudinal aim: trying out different combinations of data, especially for analysis a test bed for new combinations The Law Model from 1980 onwards aim: calculating the effects of contemplated legislation contains micro data on a sample of the population in cooperation with the Ministry of Economic Affairs up and running 24 hours a day, 7 days a week 9/22/2018

Law Model “...and when our expert has coded the proposed law changes into the terminal, we will in a few seconds witness the computer calculating the effects for a typical family - - based on a simulated model population” 9/22/2018

Consequences of archive method Data collection not linked to use Key purposes are foreseen Almost anything can be made on demand The statistical program Paid services Decided by the Board Customers Free on Internet/ StatBank.dk Full (average) cost recovery Examples: Municipality level Detailed statistics Examples: Small area statistics Even greater detail Research on micro data 9/22/2018

The filing or archive structure Administrative registers Web XML Paper Cleaning Estimation Statistical registers Aggregating Analysis Metadata SumDatabase Publishing - StatBank Denmark Nordbotten stated that the total database should be seen as a data box with 3 dimensions: Statistical unit, variable and time. During the last 10 years, Statistics Denmark has made a real movement in that direction dst.dk 9/22/2018

Micro data and longitudinal analysis Elsebeth Lynge: Occupational mortality 1970-75 Researchers’ remote access: 300 institutes 3,000 researchers 400 active projects 2 M€ 9/22/2018

Confidentiality and data protection Challenge: Keep public trust data security regulations strict organisational and technical measures limiting internal and external access to data need to know principle 1978 Register Law 9/22/2018

The case of Denmark To link or not to link - that’s the question! 9/22/2018

Difficulties in practical implementation Convincing ourselves Champions of traditional statistics University textbooks Strong management commitment Convincing the rest of the world Suspicion Bad experience history, especially WW2 Survey is the truth Jørgen Wedebye 1979: “On what grounds can anyone claim that there has ever been one single piece of correct information recorded on a Census form?” International meetings, Eurostat book 9/22/2018

Confidentiality and access to data Difficulties #2 Confidentiality and access to data The threat of a “Big Brother” society Lawsuit against Statistics Denmark in 1978-81 by five municipalities Data breaks changes in the legislation difficult to assess long-term trend identify events 9/22/2018

Difficulties #3 Functional organisation Nordbotten: “Today data for the survey of manufacturing and the wage statistics are collected separately. It will probably in many cases be more efficient to integrate the collection, i.e. collect as much as possible from a respondent when we have made a contact instead of repetitive visits or requests” slow progress Metadata allow user to determine whether the data in the archive could be recombined to create new knowledge, e.g. to confirm or reject certain hypotheses Internal as well as outside users claim this is the most important hindrance 9/22/2018

Nordbotten 1960: “In 1970, there will probably not be any need to collect a census in the traditional way” 9/22/2018

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The End!