Visual Revision Notes

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Visual Revision Notes
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Data and Information
Data has no meaning until it is put into context.
Data also need a structure before it can be
interpreted as information.
Information is a message derived from data.
Information is the meaning assigned to data by a
human.
Data is the raw values that are entered, stored
and processed in an IT system.
Information is what is produced as output or
feedback.
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Knowledge and Information

• Knowledge consists of facts.
• Using these facts and applying the rules allows
  you to interpret something correctly.

Fact 1 A cat has a tail
Fact 2 A cat has 4 tails.
Rules (more Knowledge)
Facts (Knowledge)
Information
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All organisations need to manage information,
information relates to every aspect of an
organisation. Here is an example of such
management.
The product and/or services that it offers
The market in which It operates.
Its clients, suppliers and employees
ORGANISATION
Its assets, such as office Buildings, furniture
and fittings, Telephone system, Fleet of
vehicles.
Any legislation that affects the organisation
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The flow of information between an organisation
and between the organisation and other can be
shown using this diagram.
Purchasing
Sales
Purchase order
Sales order
Copy of sales order
Copy of sales order
Invoice
Invoice
Accounts
Supplier
Customer
Payment
Payment
Delivery note
Signed Delivery note
Delivery note and goods
Delivery note and goods
Warehouse
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The basic block diagram for a computer system
shows data entering as input, being processed and
being output. Data is stored and then loaded for
further processing.
Primary data is data that arises from and
original source, for example, direct capture
onscreen from completion
Secondary data is data that is passed on or
purchased for example, mailing lists.
Data may also arise as a by-product of another
operation on original data.
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Data that is collected for one purpose may be
useful as a by product At a supermarket checkout,
for each shopper and each product that is
purchased, the bar code is recorded. If the
shopper presents a reward card, details of the
shopper can be recorded. These two sources of
data collected and collected over a period of
time can be put together to build a profile of
the products that a particular shopper buys.
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• One the main sources of error is user input
  error.
• Each field of the form is used to enter a single
  item of data.
• Some fields cannot be encoded.

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The quality of the data source has a direct
effect on the quality of information that can be
gleaned from that data. The more accurate a
source of data, then the better the quality of
the information that can be derived from it.
Garbage out
Garbage in
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A value judgement is best asked for in an open
question. Entering this data and then analysing
it is difficult without some encoding. Trying to
encode value judgements can over-simplify the
response. Form design might try to eliminate
this problem by turning an open question into a
closed one, but research shows that respondents
tend to choose middlemost options and not
necessarily answer such questions 100 truthfully.