1. The IPO Model
Input – Process - Output

2. I = Input



Input is something from the external
environment that is fed into the system.
In an information system, the inputs may
be raw data "captured" in some way or
pre-existing data which has been provided
by an external system.
In either case, the data input is provided
by an external entity.

3. P = Process



The transformation process is the most
important element of a system.
The process accepts the inputs into the system
and performs some type of operation on it which
transforms it into some other state. In the
simplest of terms, the process is at the heart of
any system.
In a computerised information system, the
process is normally the storage, retrieval and
modification of data which is accomplished by
hardware and software.

4. O = Output



Output from the system which is the result of
processing the input.
Without output, a system has no link back into
it's external environment.
Output of an information system may be reports
generated by an information system, or a
picture on a computer monitor, or even data
that is fed into another external system.

5. The IPO Model
INPUT
Data and
Processing
OUTPUT
Your analysis
starts here
The requirements of the Output, more than anything
else, will determine the requirements of the System.

6. Steps to complete an IPO Model
Steps
1.
2.
Read and understand the problem
Identify the outputs

3.
Decide what data (the inputs) is required in order to
get the required output

4.
Pick intrinsic variable names that represent the output
Sometimes these will be given to you, sometimes not,
which means you may need to invent inputs.
Once you have the outputs and the inputs you need
to determine how the inputs can be transformed
into the required outputs. This is a dynamic process
which may mean you need to continually return to
the previous steps.

7. Example
Analysis for CelsiusToFahrenheit Program:

Input
degrees Celsius

Process
F = C * 9/5 + 32

Output
degrees Fahrenheit

8. Problem Statement
A student's final grade for a course is a
weighted average of two tests, a final
exam, and four projects. Each test is
worth 15%, the final is worth 30%, and
the projects are worth a total of 40%
(10% each). Given a student's grades for
all of these assignments, calculate the
final score.
What output/s are require?

9. Problem Statement
A student's final grade for a course is a
weighted average of two tests, a final
exam, and four projects. Each test is
worth 15%, the final is worth 30%, and
the projects are worth a total of 40%
(10% each). Given a student's grades for
all of these assignments, calculate the
final score.
What input/s are required?

10. Problem Statement
A student's final grade for a course is a
weighted average of two tests, a final
exam, and four projects. Each test is
worth 15%, the final is worth 30%, and
the projects are worth a total of 40%
(10% each). Given a student's grades for
all of these assignments, calculate the
final score.
What process/es are required?

11. Problem Statement
A student's final grade for a course is a weighted average of two tests, a final
exam, and four projects. Each test is worth 15%, the final is worth 30%, and the
projects are worth a total of 40% (10% each). Given a student's grades for all of
these assignments, calculate the final score.
Input
Get
Get
Get
Get
Get
Get
Get
Result
Result
Result
Result
Result
Result
Result
of
of
of
of
of
of
of
Test1
Test2
FinalExam
Project1
Project2
Project3
Project4
Process
1.
2.
Calculate FinalScore
FinalScore = (Test1 + Test2)
* 15/100 + Test3 * 30/100 +
(Project1 + Project2 +
Project3 + Project4) * 40/100
Output
FinalScore

12. Self-Check
1. Consider a student file that contains the following data fields:
First Name Last Name Course Grade
Would this set of data be suitable and sufficient to use to test each of the
following programs? Explain why or why not.





A program that
A program that
A program that
A program that
A program that
prints a
prints a
prints a
prints a
prints a
list
list
list
list
list
of
of
of
of
of
SDD students
students nearly failing - those with a grade is less than 50%
student on the Principal’s list
students from Parramatta
female students.
2. Construct an IPO chart for a program that gives an employee $50
bonus for every 500 items sold in a week.
3. Construct an IPO chart for a program that will output a student's
grading based on letter grades (A, B, C, D, or F) in five courses.

13. 4. IPO Examples
Input
Processing
Output
original number
1.
squared value
2.
calculate the squared value by multiplying the original number by
itself
display the squared value
Input
Processing
Output
state1 sales
state2 sales
commission rate
1.
2.
commission
3.
enter state1 sales, state2 sales, and commission rate
calculate the total commission by adding the state1 sales to the state2
sales, and then multiplying the result by the commission rate
display the total commission
Describe what these two IPO models
are doing…