Transcript Data Sources

Data Sources
Chapter 1
Introduction
• This presentation covers the following:
– Primary and Secondary sources of information
– Advantages and Disadvantages of using different
sources of information
– Static and Dynamic sources of information
– Quality of data
Data Source
• Data doesn’t magically appear. Someone
must have collected it.
• Likewise, information comes from data and
what we do with it.
• Where we get the data from is known as the
source.
Primary (Direct)
• This is data collected
from it’s original source.
• Think of it as data which
has been physically
collected by you.
Secondary (Indirect)
• Secondary data can come in two ways:
– Collecting data for one reason and then using the same data for
another reason. For example, collecting data about plane tickets to
make sure they aren’t over booked, and then using the same data to
find out which destination was the most popular.
– Other organisations/people may collect data and you can then use
the data which they have collected.
Primary vs Secondary
• Primary:
– Advantages:
• You can control how the data is collected
• You can specify the data which is to be collected
• You can be more dynamic with your data collected based on
previously recorded data entries.
– Disadvantages:
• If you need data you need to get it yourself – this can take
time.
• The amount of data you can collect could be small compared
to a secondary source.
Primary vs Secondary
• Secondary:
– Advantages:
•
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Can get a large range of data
Can get data from a range of providers/sources
Can get data immediately if it has already been collected
Some analysis may have already been carried out on the data
– Disadvantages:
• May not be able to tell if it is biased or not?
• You can’t be sure if the data is accurate
• You may not have all the facts about how it was collected which
means it might not be suitable for your need
• You might have to pay for the information
Take note:
• Describe the difference between primary and secondary
sources giving an example for each one using the context of
a pet food company.
• Describe two advantages of using an original source to
collect information on how good different MP3 players are.
• Give two examples where by using indirect sources are
more suitable than using direct sources. For each situation
explain why.
• Describe one situation where it would be advantageous to
use both direct and indirect sources of information.
Static and Dynamic
• Static:
– Once created does not change
• Dynamic:
– Once created it can be modified and updated.
Static
• Think of static
information sources as
a hard copy.
• Information in a book
can not be updated
unless a new book is
released.
Dynamic
• Web pages are
excellent examples of
dynamic data sources.
• Some websites refresh
automatically with new
content all the time.
• BBC Sports has ‘As it happens’ updates which show what
is happening in an event.
Take note:
• What is the difference between static and dynamic
sources of information?
• Give two reasons why websites are classified as
dynamic sources of information.
• Give two examples where static sources would be
preferable to dynamic sources.
• What problems could you face when using dynamic
sources? Give two examples.
Take note:
• Create a two column table which compares CD-ROMs and
Websites as sources of information.
• Use this table to help you out:
CD-ROM
Websites
There is a limited amount of information The WWW provides large quantities of
available.
information.
Does not require internet access.
Only people with internet access can
access the information.
Data cannot be updated quickly.
Updates can happen within seconds of
new data being received.
...
...
Quality of information
• GIGO:
– Garbage In Garbage Out
• If you enter incorrect
data into a computer
it will return
inaccurate results.
Quality factors
• There are six factors that determine how good
data is (depending on the situation):
– Accuracy
– Relevance
– Age
– Completeness
– Presentation
– Level of detail
Take note:
• Describe each of the six factors affecting the
quality of the information.
• For each factor, give an example of how it affects
the quality of the information produced.
• Demonstrate, using examples, how one factor
can have a knock-on effect and influence other
factors.