Presentation on theme: "DLI Orientation: Concepts"— Presentation transcript:
1 DLI Orientation: Concepts A Framework for Thinking about Statistical InformationChuck HumphreyData LibraryUniversity of AlbertaApril 2004
2 Statistical Information Two models for identifying and selecting appropriate statistical information:A chart of statistical informationDistinguishing statistics & dataDistinguishing aggregate data & microdata
3 Statistical Information Continuum of accessMatching dissemination channels with desired products
4 Statistics or Data Statistics Data numeric facts/figures created from data, i.e, already processedpresentation-readyDatanumeric files created and organized for analysisrequires processingnot ready for display
9 Chart of Statistical Information This is a typology of the categories or classes of statistical information. Remember the relationship between statistics and data, however, is causal. Statistics are created from data.
13 In PrintRely on yearbooks, statistical abstracts, catalogues, and indexes to locate statistics in print.Examples of online indexes to print resources:Statistical Universe and TablebaseExample of an online catalogue that includes print resources:Statistics Canada’s Online Catalogue
15 Online Statistics Example of e-publications Example of e-tables Statistics Canada Downloadable Publications (DSP)Example of e-tablesCanadian Statistics (STC Website)Example of statistical databasesCANSIM II (STC Website, E-STAT, CHASS)
16 E-Publications Tend to be available in PDF format Can use the “Select Text” Tool in the Adobe Reader and copy columns to another application
18 E-Tables Tend to be displayed in HTML May provide a pull-down list to view other categories in the tableSome e-tables will provide an alternate format for the table that can be downloaded (e.g., the Census tables are available in comma-separated ASCII, IVT, and print-friendly formats)
20 DatabasesOften use HTML forms to define the statistics to be retrievedMay offer a variety of output formats for the retrieved statistics (e.g., E-STAT provides IVT format for Beyond 20/20, graphs, charts, maps, and ASCII formats for spreadsheets and databases)
24 Aggregate DataAggregate data consist of statistics that are organized into a data structure and stored in a database or in a data file.The data structure is based on tabulations organized by time, geography, or social content.
25 Aggregate Data Example: CANSIM II Data Structure Time Geography Social Content
26 Aggregate DataTime series data have long fueled econometric models based on macro-economic indicators.Comma-separate values (CSV) have become an important format for time series data, which is often manipulated in Excel if not analyzed in a spreadsheet.
27 Aggregate Data Example: CENSUS Data Structure Time Geography Social Content
28 Aggregate DataIncreased availability of GIS software has created greater demand for Census statistics organized as aggregate data.Beyond 20/20 has become a popular tool for reshaping census statistics from 1996 and 2001 for use with GIS software.DBF is the most commonly used format to share census statistics with GIS software.
29 A map from E-STAT of Montreal Census Tracts Aggregate Data
30 Aggregate Data“Small area statistics” are a special category of aggregate data. These data files consist of statistics for small geographic areas usually calculated from a population or manufacturing census or an administrative database with enough cases to create accurate summaries for small areas.
31 Aggregate Data Example: Cause of Death (HID) Data Structure Time GeographySocial Content
32 Aggregate DataAlso known as “cross-classified” tables, these files tend to be made of statistics constructed from social-content variables. Examples of cross-classified tables in DLI are found in education and justice.
34 MicrodataThis is raw data organized in a file where the lines in the file represent a specific unit of observation and the information on the lines are the values of variables.There are different types of microdata files, which will now be discussed.
35 Confidential Microdata Master files: these files contain the fullness of detail captured about each case of the unit of observation. This detail is specific enough that the identify of a case can often be disclosed easily. Therefore, these files are treated as confidential.
36 Confidential Microdata Share files: these are confidential files in which the participants in the survey have signed a consent form permitting Statistics Canada to allow access to their information for approved research.These files consist of a subset of the cases in the master file.
37 Confidential Microdata In summary, confidential microdata get grouped into two types:master files and share files.
38 Public Use MicrodataThese microdata are specially prepared to minimize the possibility of disclosing or identifying any of the cases in a file, i.e, participants in a survey.The original data from the master file are edited to create a public use microdata file.
39 Public Use Microdata Steps in Anonymizing Microdata Remove of all personal identification information (names, addresses, etc);Include only gross levels of geography;Collapse detailed information into a smaller number of general categories;Cap the upper range of values of variables with rare cases;Suppress the values of a variable; orSuppress entire cases.
40 Public Use Microdata Statistics Canada PUMFs Only available for select social surveys that undergo a review of the Data Release Committee, an internal Statistics Canada committee.No ‘enterprise’ public use microdata.
41 Public Use Microdata Statistics Canada PUMFs Almost all PUMFs consist of cross-sectional samples, that is, samples where the data have been collected from respondents at one point in time.Longitudinal samples, where data are collected from the same individuals two or more times, are difficult to anonymize and maintain any useful information.
42 Synthetic MicrodataThese data files have been created by author divisions to assist with the analysis of confidential data files.The files provide the full variable structure of the confidential microdata but do not contain any real cases.They are intended to be used by researchers wanting to submit a file of commands in a statistical package’s language for remote job submission.
43 Synthetic MicrodataThey are also being used by those with approved projects in Research Data Centres to help prepare their analysis strategies prior to working in an RDC.Synthetic files are also commonly referred to as “dummy files,” although a more technical use of this term does exist for this specific type of synthetic file.
44 Synthetic MicrodataA variety of synthetic file types are being created and tested by author divisions.One type has no real data but does contain a complete set of real variables. This type is the more technical reference to a dummy file.Another type has a mix of real data but no real cases. The purpose of this type is to provide -- in the aggregate -- results that should be close to an analysis of the real microdata file.
45 Synthetic MicrodataUsers of these files must be advised that none of the analytic results from these files should ever be reported. Their only purpose is to help researchers construct their statistical analysis programs to guard against syntax errors that might exist in their setup.The DLI FTP site clearly distinguishes synthetic files from real microdata files.
47 Summary: First ModelThis first model provides a way of thinking about the types of statistical information that exist.Is the information Statistics or Data?If Statistics, is the information in print or online?If online, is it in an e-pub, e-table, or database?If Data, is the information aggregate data or microdata?
48 The Second ModelIt is one thing to know about the variety of statistical information that exists, but access to this information is a separate issue.The second model describes the various dissemination channels through which access is provided to statistical information by Statistics Canada.
49 Continuum of AccessStatistics Canada provides access to its statistical information through a variety of services and initiatives that function as dissemination channels.Think of this variety as constituting a continuum along which levels of access are provided.
50 Continuum of AccessThere are three characteristics that make up this continuum:Cost : which runs from free to expensive;Restrictions or conditions : which run from open or no restrictions to very restricted; andType of Information : which runs from statistics to data.
51 Continuum of Access ACCESS CHANNELS Depository Service Program OpenFreeStatisticsRestrictedExpensiveDataDepository Service ProgramRemote Job SubmissionStatistics Canada WebsiteData Liberation InitiativeCustom TabulationsResearch Data Centres
52 Statistics Canada Website Free, Open, StatisticsThe Daily is an important source of publicly-released official statistics. It has been available on the Website for several years and was the primary source for free statistics in the early years of the Statistics Canada website.
53 Statistics Canada Website Free, Open, StatisticsWith the introduction of Community Profiles from the 1996 Census in 2000 and more recent offerings from the Health Statistics Division, this dissemination channel has had a big increase in the amount of statistics available at the national, provincial, CMA, CSD, and Health Region levels.
54 Depository Service Program Free, Open, StatisticsThe Depository Service Program (DSP) has provided public access to government information for over 75 years. Through a network of public, special, and academic libraries, the Treasury Board has paid Federal Departments to release publications to the public through the DSP.
55 Depository Service Program Free, Open, StatisticsStatistics Canada has a large series of publications that it makes available through the DSP. Many of these titles are available online in PDF format and are part of the Statistics Canada Downloadable Publication series.While these statistical publications are free, the public is required to go to a DSP library to access them.
56 Data Liberation Initiative Fee, Licenced, Conditional Access, Data and StatisticsDLI provides a wider range of statistical information than the Statistics Canada Website or the DSP, but access in no longer free and rules apply those who are eligible to use these materials.This is a move away from free-&-open to fees-&-conditional access.
57 Data Liberation Initiative Fee, Licenced, Conditional Access, Data and StatisticsDLI provides member institutions in the post-secondary educational sector with access to all “standard data products,” which consists of the statistical databases, public use microdata files, and geography files listed for sale in the Statistics Canada Online Catalogue.
58 Data Liberation Initiative Fee, Licenced, Conditional Access, Data and StatisticsPatrons of this service must hold a current affiliation with a member institution and are restricted in their use of these materials for teaching, scholarly research, or institutional planning.Furthermore, secondary redistribution of DLI materials is not allowed.
59 Customized Tabulations Pay-per-view AccessA long-term dissemination channel within Statistics Canada has been custom tabulation services.This is a contract service with Statistics Canada to produce tables from surveys or the Census that have not been produced for public release.Each customized product comes with its own licence.
60 Remote Job Submission AKA, Remote Data Access (RDA) This is a relatively new service for a select number of surveys.The terms of access vary among the author divisions offering this service. Some charge a fee (e.g., access to YITS and PISA is $75 a run), while other divisions do not charge. The Health Statistics Division requires a proposal to access the surveys for which it provides remote job submission.
61 Remote Job Submission AKA, Remote Data Access (RDA) Synthetic files have been created to assist with the preparation of the statistical command files that are submitted for remote processing.An analysis is prepared in the command language of a statistical package supported by the author division (SAS or SPSS, e.g.) and submitted via to the division.
62 Remote Job Submission AKA, Remote Data Access (RDA) All results are screened by the author division for disclosure issues prior to the output being sent to the researcher who submitted the job.This dissemination channel provides a means of producing analysis from confidential data files with conditional approval and in some instances for a fee.
63 Research Data Centres Restricted Access to Confidential Data Research Data Centres house select confidential data files in a controlled Statistics Canada office environment.Access is provided on a project-by-project basis.A SSHRC-administered application process is used to evaluate the proposed use of the confidential data.
64 Research Data Centres Restricted Access to Confidential Data Furthermore, a security clearance with Statistics Canada must be passed.With approval from both the SSHRC peer review and the security clearance, the members of a research project must undergo an orientation to the RDC, swear an oath to the Statistics Act, and sign a contract with Statistics Canada.
65 Research Data Centres Restricted Access to Confidential Data The advantage of RDC access over Remote Job Submission is that researchers get to work directly with the confidential data source.
66 Statistical Information available through Statistics Canada Different ServicesService:StatisticsCanada WebsiteDepositoryServiceProgramData LiberationInitiativeCu$tomizedTabulations &Pay per ViewRemote JobSubmissionResearch DataCentresWho isEligible &Conditions:General Public:available on theInternet atDesignatedDSP Libraries& their Users:available on sitePost-secondaryAcademic:restricted toteaching andresearch purposesIndividuals:contract betweenSTC andindividualApprovedResearchers:SSHRC peerreview & deemedSTC employeeProducts:- The Daily- Canadian- Census- Statistical profilesof Canadiancommunities- Downloadablepublications- Paper publica-tions- Electronic pub-lications, whichincludes priceddown-loadablepublications &select CD ROMSStandard dataproducts:aggregate databases, microdatafiles andgeography filesTables fromconfidential filesthat are speciallyproduced byStatistics Canadafor a fee andaccess tospecializeddatabases“Dummy” orsynthetic files tobuild analysissetups that mustthen be submittedto Stats Can forprocessingConfidential datafiles from thelongitudinalsurveys begun inthe 1990’sNotesWarning: someparts of the Websiteare fee-basedSome DSPlibraries provideoff-site access toauthenticatedusersInterface toCANSIM I andTrade Analyzeravailable throughCHASS (Universityof Toronto) bysubscriptionSpecializeddatabases includeOpenFreeStatisticsRestrictedExpensiveDataACCESSServices availableApplications canfor selected titles.now be submittedCANSIM II andRemote jobthrough theTrade Analyzersubmission is theSSHRC Web site.most developedfor NPHS.
67 Using the Two ModelsCombining these two models should assist you in identifying and selecting appropriate statistical information.The types of statistical information should help you identify an appropriate product, while the continuum of access should help you locate the channel or channels through which the statistical information is disseminated.
68 Using the Two ModelsHopefully, you will find this framework useful in your data reference interviews, which is a separate topic in this orientation, and in navigating the DLI FTP site for various statistical information.
69 WarningRemember that while Statistics Canada is an important source of statistical information in our country, it is not the only source.Other important sources include other federal government and provincial departments, data libraries and archives, non- & inter-governmental agencies, and commercial vendors.