Data and quality of data

Data and quality of data

1. Encoding

   • Involves shortening data when putting it into a computer system. Encoding has numerous benefits
   • Examples of Encoding
     • Sex - M=male F=female
     • Teachers Initials on timetable e.g. Jack Desambrois = JD
     • Airline codes on airport departure boards – BA (British Airways) / FCA (First Choice Airways)
   • Encoding data has the following advantages
     • It saves time because entering encoded data is quicker
     • There are fewer characters so less storage space is needed
     • Less storage space is used which means that it is often faster to access coded data
     • There is less chance of human typographical errors (accidentally pressing the wrong keys)

2. Storing Data

   • Advantages
     • It can be Cheaper because less money is used on overheads as less space is needed to store filing cabinets
     • It is easier and quicker to back up data elsewhere using the internet
   • Disadvantages
     • Training needed to show staff how to use computers which can be expensive
     • The ease of transferring data is a security risk. Protection from hackers is needed

3. Validation Checks

   • Used to make sure that only sensible data is entered into a computer
   • Examples
     • Batch total
       • Checks that something is not missing by adding together a number field in different records and checking the total
         • E.g. If an invoice has three items costing 1p, 2p and 3p, the computer will look for a batch total of 6p.
     • Hash total
       • Exactly the same as a batch total, but the field checked is meaningless
         • E.g. If a company signs up three new customers with phone numbers ending with 2, 4 and 3, the computer will look for a hash total of 9
   • Transcription
     • Errors sometimes occur when copying data to a computer (when reading bad handwriting, for example)
   • Transposition
     • Errors can sometimes happen when characters are accidentally swapped around (accidentally pressing Q instead of W, for example).
   • Verification
     • checks can be used as techniques to overcome these possible sources of error. Verification just means stopping errors when data is copied from one medium to another
       • Examples
         • Double Keying
           • Data is entered twice to check that both sets of data matches up e.g. Creating passwords when registering for social networking websites
         • Visual Check
           • Also known as proofreading (double-checking something) e.g. Looking over a CV before sending it to somewhere you want to work.
         • Parity Check
           • Checks that data is correct when it is transmitted (sent) somewhere e.g. Uploading files to a website will involve some kind of parity check.