C. Demetriou (2009) September 14, 2009 1
ž Data is simply raw facts or figures
ž Can be made up any alphanumeric
characters
ž It has no context
ž Is has no meaning
ž e.g.
› 220480
› R254RSM
› 4009041222453
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ž Information is data with the addition of
Meaning, Context and Structure.
ž Information is useful and can be
interpreted
ž Information is FACT!
Information
Data Meaning Context Structure
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› 220480
– 22/04/1980 is a date
– my date of birth
› R254RSM
Context
Meaning
– R254 RSM is a car registration
– Suzuki Swift
› 4009041222453
– Is a bar code
– for instant coffee
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ž How do we convey information to one
another?
› Text
› Graphically/Symbols
› Pictures/Animation/Videos
› Sound
› LEDs
ž What are the Advantages & Disadvantages
of each?
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Text
› Take the following statement:
"Fruit flies like a banana"
– Do small insects prefer a banana
– or does fruit glide through the air in
a way similar to a banana
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Representation Methods
ž Graphically
› Numbers are easier to visualise in graphical
format
ž Symbols
› Language-independent
› Universal recognition
– Some symbols may have different meanings
so care is needed
– Some symbols are recognised but their
meaning is not so well known.
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ž What is knowledge?
› Knowledge is the result of interpreted
information.
– “We need more tins of baked beans” might
be the knowledge acquired from interpreting
the information given in the stock report.
› Knowledge can be used to setup rules.
– E.g. “It is hotter in July therefore we will sell
more ice cream, so we need to increase the
order for ice cream in June.”
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Difference Between
Information and Knowledge
ž Information is based on facts
ž Knowledge is based on rules, and these
rules are based on probabilities, not
certainties:
› “Double clicking an icon in Windows will
open an application”
– This is not information as it is not a certainty.
› “Icons are pictures”
– This is information – NOT knowledge
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ž When data is stored it has to stored in an
appropriate type, a data type
› Boolean
– Can hold one of two values – True/False, 1/0
› Real
– Holds decimal numbers
› Integer
› String
– Holds text (can include numbers and symbols)
› Date/Time
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ž Are you married?
ž £10.56
ž Surname
ž Wellington Road South
ž 0161 958 3132
ž Smoker
ž SK1 3UQ
ž VAT Rate
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ž Original Source
ž Indirect
› Data passed on
› Data purchased
ž Archive
ž Processed Data
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Gathered from an original
source
ž Collected as part of a transaction in a
shop
› e.g Credit Card Number
ž Collected in a survey
› e.g. Recorded on an OMR form
› Recorded in an interview
ž Collected using sensors
› E.g. weather station
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Indirect Source
ž Data used for a purpose different to that
for which it was originally collected
– E.g. a credit card firm uses data about each
transaction to bill the customer, then used
the data to find out about their spending
habits to send them focused adverts.
ž Data Passed on/Purchased
– Junk mail often is sent to people who have
given their details away for another purpose.
Could be details used in a competition that
have been sold to another company.
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ž Archive
› Data which has been recorded but is old
and has been filed away.
– Old Student records
– Archived footage on the BBC
ž Processed data
› Data which has been processed can
produce new sets of data
– Sales figures for stores / regions
– Compiled data for departments
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ž There is often confusion between a data
archive and a backup.
ž A classic backup application takes
periodic images of active data in order
to provide a method of recovering
records that have been deleted or
destroyed.
ž Most backups are retained only for a few
days or weeks as later backup images
supersede previous versions.
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ž Essentially, a backup is designed as a short-
term insurance policy to facilitate disaster
recovery, while an archive is designed to
provide ongoing rapid access to decades of
business information.
ž Archived records can be placed outside the
traditional backup cycle for a long period of
time, while backup operations protect active
data that's changing on a frequent basis.
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ž Information in ICT can come in two forms
› Static (Does not change)
– Books
– CD encyclopaedia
– Internal Help files
› Dynamic (Changes)
– Internet Pages
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ž When would you consider information to be
bad quality?
ž College Enrolment form
› You all filled in an enrolment form
› How could the data on the form be of quality?
ž What does Stockport College do to ensure the
data collected is of good quality?
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Factors affecting quality of
information
ž Accuracy
ž Relevance
ž Age
ž Completeness
ž Presentation
ž Level of Detail
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ž It is commonplace to code data.
ž This is changing the original data into a
shortened version in order to store it in
the computer.
ž Storing days of the week as Mo, Tu, We
etc, or months of the Year as Jan, Feb,
Mar…
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Problems of Coding Data
ž Precision of data coarsened
› E.g. Light Blue coded as Blue
ž The user needs to know the codes utilised
› If the user is not aware of the codes then they
cannot interpret the data
ž Coding of Value judgements
› E.g. “Did you like the film?” to be coded as a
judgement of 1-4. This will be coded differently
by different people and makes comparisons
difficult.
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ž Less storage space required
ž Comparisons are shorted and can
therefore be made quicker, thus
speeding up searches
ž A limited number of codes exists aiding
in validation of input
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ž Validation ensures that reasonable data
is entered into a system, it does not
ensure the accuracy of data.
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ž Range Check
› To check that the value entered is within a
pre-determined range.
– Between 1 and 10 for movie ratings
ž Type Check
› To check if the data entered is of the correct
data type
– “66” is not a Surname
– “Frank” is not a Date of Birth
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ž Check Digit
› Used to see if a number entered is a valid
number using an algorithm
– Credit card numbers are checked in this way
ž Length
› To check if data entered falls within a certain
size, minimum and maximum.
– Post codes must be between 5 and 7
characters long (M1 7HR or WC1B 5BE)
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ž Lookup
› Checks to see if the option chosen exists
already on the system or from a pre-
determined list, e.g. Male or Female
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ž Picture or Format check
› Makes sure that the data entered follows a
known pattern (e.g. Postcodes, National
Insurance Numbers)
ž Presence Check
› Makes sure that data has been entered into
mandatory fields
› Often indicated by an asterisk on a form
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ž Verification does not ensure the data is
correct but that it is entered correctly
and reduces errors.
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ž Double entry with automatic comparison
› E-Mail addresses
› Passwords
ž Problem:
› May have made the same error and
therefore it is not picked up
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ž Proof Reading
› Entering data
› Reading it back
to check it is
correct
ž Problem:
› Blurred eyes
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Information costs money to produce.
ž Hardware
› To collect, analyse and output the data
› Storage space to hold the data
› Purchasing of equipment and updating the equipment
ž Software
› Required to analyse the data and to report on the results
› Software licences
› Maintenance agreements
ž Manpower
› People employed to collect or enter the data
› Maintenance of hardware and software
ž Additional:
› Training of staff
› User manuals
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ž Information is used for a variety of purposes:
› Decision Making
› Planning
› Control
› Recording Transactions
› Measuring Performance
ž Intended use affects its value.
ž Costs must be balanced against the
benefits:
› the greater the benefit the higher the cost you
will be prepared to pay.
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ž Input
› Taking data external to the current system and
entering it into the system.
ž Processing
› Manipulating the data into information – usually
into a form understandable by the user
ž Output
› Taking data within the system and presenting it
to the user, or in a format specified by the user
(e.g. on disk)
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ž Storage
› Holding either the input or the results of
processing for use at a later date.
ž Feedback
› Where the output of the system influences
the input.
› There is a continuous loop of input resulting in
output which in turn affects the subsequent
input.
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Input Processing Output
Storage
Feedback
You need to memorise this diagram as you may be asked to
recreate it or apply it in the exam.
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