Data Extractors Summary of Features Delivery Strategies Best

Data Extractors Summary of Features Delivery Strategies Best Practices C. Humphrey

Summary of Features Study selection methods Variable selection methods Case selection methods Methods of downloading or retrieving subsets Simple analysis capabilities C. Humphrey

Study Selection Methods simple an extractor for a single study list of study titles organized by subject headings a searchable catalogue of titles or variables within studies C. Humphrey

Variable Selection Methods list of variable names a subject index linked to a list of variables Either may include the data dictionary entry for individual variables. C. Humphrey

Case Selection Methods a set of pre-selected demographic variables declare through Boolean expressions using variables within a study through a random selection of cases C. Humphrey

Methods of Retrieval use of an ftp site, anonymous or logon download from a Web page C. Humphrey

Simple Analysis Capabilities frequency distributions or descriptive statistics for individual variables simple tables of two-way tabulations or descriptive summaries simple charts or graphs C. Humphrey

Delivery Strategies full client application a helper application or plug-in CGI and database applications a network programming application C. Humphrey

Delivery Strategies full client application independent program written to communicate with a specific server ü advantage: the client has complete communication control with the server ü disadvantage: the development costs to program and support a full client C. Humphrey

Delivery Strategies a helper application or plug-in an application operating in conjunction with a Web browser ü advantage: the Web browser handles the network communication ü disadvantage: the development costs to program and support the application C. Humphrey

Delivery Strategies CGI and database applications the use of Web forms to drive database requests C. Humphrey ü advantage: the Web browser handles the network communication and supports multiple platforms ü disadvantage: feeding and caring the database needs standard products

Delivery Strategies a network programming application network-programs operating with a Web browser ü advantage: the same Web advantages as before plus added functionality ü disadvantage: same database concerns as before plus the costs of programming C. Humphrey

Best Practices modularity based on standards easy to migrate portable off-the-shelf C. Humphrey

Best Practices modularity a system of single-tasked utilities that communicate easily among themselves C. Humphrey

Best Practices based on standards accepted practices for organizing and building systems the communication among modules depends on standards C. Humphrey

Best Practices easy to migrate easily adapt with changes in new technology primarily, the data documentation and data must outlive current software and hardware C. Humphrey

Best Practices portable easily used with a variety of systems, including MS/Windows, Unix and Mac. OS C. Humphrey

Best Practices off-the-shelf acquire components that are commercially produced C. Humphrey

Directions to Take CARL CFI proposal phone conference Tuesday, Nov 30 Future Directions for DLI moving from a pilot project to a permanent program Strategies for COPPUL C. Humphrey