7. Writing Field-developed Applications › 7.2 Deciding What the Application Must Do › 7.2.1 Input Source

7.2.1 Input Source

The need to manage information that is not currently being
managed is the reason for writing a field-developed
application.  The information that your FDA is going to
manage is, in CA MICS terminology, an information area.

Having identified the information area, the source or sources
of data should be apparent.  Consider several criteria for
the suitability of the data sources when choosing the source
on which your FDA will rely.

o  The data must be available on a regular basis (for
   example, daily) in a reliable fashion.

   The source data needs to be available when the CA MICS
   daily update cycle is scheduled.  Interruption in this
   data will certainly mean an interruption in data appearing
   on the online database.  Long term interruption may affect
   the accumulation of data for trend analysis.  Even short
   term interruptions can affect other CA MICS products if
   the FDA is installed in a production database unit with
   other products.

o  The data must be structured enough to allow its analysis
   by a SAS program.

o  If the data is manually generated, there should be
   appropriate verification for correct contents.

o  The data should describe some measurable quantity for
   which your site has performance or service objectives.

Documenting the data source or sources is useful when coding
or analyzing the data produced.

Specifically, a description of the media and data sets from
which the source data is received is useful when coding the
MCG statements.  Descriptions of the data elements in the
records and their source and content are also helpful.  These
descriptions are used in formulating MCG code for output
files, and help identify the type and length coding of data
elements.