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Systems Analysis and Design
Part 1
Analysis Stage
Systems Analysis and Design
 As
businesses grow, they will need to look
at how they process their data.
 Developing
new systems is very expensive
in time, people, and money.
 The
way a company approaches this task is
vital to its success as a business.
The systems life cycle
 Systems
of any kind have a life cycle.
 Systems
are created, they develop, they
mature, they eventually lose their efficiency,
then they are replaced.
 The
systems analyst will follow this life cycle
to complete the stages that take place when
a system is being designed and developed.
Collecting data for analysing the
current system
 There
are four main ways to collect
information about the current system, as it is
being used at the moment, each having
advantages and disadvantages.
 The
systems analyst must decide depending
on the current situation what methods he will
use to collect information from the people
who work on the system first-hand.
Collecting data for analysing the
current system
 The
systems analyst will use the following
four ways to collect system information he
requires from the current system users.
• Interviews
• Observation
• Questionnaires
• Using existing documentation
In pairs, takes 10 minutes to use the internet to search for
information, and write notes about data collection methods
Interviews
Description
Advantage
Disadvantage
Observation
Description
Advantage
Disadvantage
Questionnaires
Description
Advantage
Disadvantage
Using existing documentation
Description
Advantage
Disadvantage
Based on your findings, decide which would be the best
way to collect information in the following situations
Situation
A small group of people have detailed
knowledge of the current system
Only a few people have limited
knowledge of how the present database
is constructed
You need to understand how information
and documents move around the
organisation
Many people have views about how
effective the current system is and who
can provide answers to a number of
specific questions
Method
Method
Observation
Description
Involves watching
personnel using the
existing system to
find out exactly how
it works.
Advantages
The analyst obtains
reliable data. It is
possible to see exactly
what is being done.
It is a relatively
inexpensive method.
Questionnaire Involves sending out The questions can be
s
questionnaires to
answered quite quickly.
the work force and/or
to customers to find
out their views of the
existing system and
find out how some of
the key tasks are
carried out.
It is a relatively
inexpensive method.
Individuals can remain
anonymous if they
want.
It allows quick analysis
of the data.
Disadvantages
People are generally
uncomfortable being
watched and may work in a
different way.
If workers perform tasks that
violate standard procedures,
they may not do this while
being watched!
Often the number of returned
questionnaires is low. The
questions are rather
inflexible since
they have to be generic.
There is no immediate way to
clarify a vague or incomplete
answer to a question.
Method
Interviewing
Looking at
existing
paperwork
Description
Involves a one-toone question-andanswer session
between the analyst
and the
employee/customer.
Advantages
It gives the opportunity to
motivate the interviewee into
giving open and honest answers
to the analyst's questions. It
allows the analyst to probe for
more feedback from the
interviewee, as it is easier to
extend a question. It is possible
to modify questions as the
interview proceeds and ask
questions specific to the
interviewee. It is a good method
if the analyst wants to probe
deeply into one specific aspect
of the existing system.
Allows the analyst
It allows information to be
to see how the
obtained which was not possible
paper files are kept, by any of the other methods.
look at operating
The analyst can see for
instructions and
themselves how the paper
training manuals,
system operates. It allows the
check the accounts, analyst to get some idea of the
etc.
scale of the problem, memory
size requirements, type of
input/output devices needed, etc.
Disadvantages
It can be rather time
consuming.
It is relatively
expensive, due to
the use of the
analyst's time. The
interviewee cannot
remain anonymous.
It can be very time
consuming.
Because of the
analyst's time, it is
a relatively
expensive method.
Information collection
 Once
the systems analyst has collected as
much information as he can, he will bring it
together in a way so that the current
system can be described fully.
 He
will create flowcharts to show the flow
of information, where it is stored, how it is
accessed and by whom.
 This
will make it possible for the system
analyst to determine the strengths and
weaknesses of the current system.
Outcomes of Analysis Stage
 The
outcome will be a report to
management outlining the requirements
that any new system should fulfil.
people call it the “terms of
reference” as it can be used as a
reference, in order to ensure that any
design proposal does in fact meet the set
of requirements.
 Some