unit 2. basic techniques - upmocw.upm.es/lenguajes-y-sistemas-informaticos/software...it is also...

Software Quality

Unit 2. Basic techniques

Calidad del Software

Index

1. Techniques for quality improvement and troubleshooting .

2.Teamwork: Brainstorming, affinity diagram, catchball.

3. The 7 statistical quality tools: check sheets, histogram, Pareto’s diagram, diagram of dispersion, cause-and-effect diagram, process flow diagram.


They are useful tools for:

• Look for defects.

• Data analysis and checking for

control limits.

• Staff problem detection.

• Systems improvement.

...

Quality basic techniques?


Problems resolution must be an usual practice in an Organization quality committed.

“Anyone makes an error. But only a stupid insists on it”

Robertine Maynard

IMPROVEMENT AND PROBLEMS

RESULUTION


Improvement and problems

resolution – PDSA cycle

DO

ACT

DAS

4. Implement

6. Standardize the solution7. Plan for the future

PLAN1. Identify the opportunity

2. Analyze the process

3. Develop the optimal

solutionPSTUDY

5. Study the results


1. IDENTIFY THE OPORTUNITY

Main goal of the phase is to identify

and prioritize opportunities for

improvements.

a) Identify the problem

b) Form the team

c) Define the scope




1.a IDENTIFY THE PROBLEM

• Is the problem important and why?

• Will problem solution contribute to

the attainment of goals?

• Can the problem be defined clearly

using objective measures?




1.b FORM THE TEAM

• Usually is a working group.

• If the problem is of multifunctional

nature the team should be selected

and tasked by the quality council.

• The team leader is selected and

became in the owner of the process

improvement.




1.c DEFINE THE SCOPE

• A problem well defined is half solved

The problem exits and it is clearly described and it

is easily understood.

The effect has been stated: what is wrong, when it

happens, and where it is occurring, not why it is

wrong or who is the responsible

What is known, what is unknown, and what needs

to be done.

Describe facts and not judgments.

Emphasizes the impact on the customers.




2. ANALIZE THE CURRENT PROCESS

The objective of the phase is to understand

the process. Key activities are:

a) Define process boundaries

b) Determine levels of customers

satisfaction and measurements needed

c) Gather data

d) Identify root causes





First steep for the team: develop a

process flow diagram.

Second steep: define performance

measures.

Third steep: collect all available data

and information.

Fourth steep: develop a plan.





Questions that plan answers:• What problem or operation do we wish to learn

about?

• What are the data used for?

• How many data are needed?

• What conclusions ca be drawn from the collected

data?

• What action should be taken as a result of the

conclusion?




3. DEVELOP THE OPTIMAL SOLUTION(S)

The objective is to establish potential

and feasible solutions and to recommend

the best solution to improve the process.




4. IMPLEMENT CHANGES

This phase prepares the implementation plan,

obtaining the approval, and implementing the

process improvement.

The content of the implementation plan must

fully describe:



Why will it be done?How will it be done?When will it be done?

Who will do it?Where will it be done?


5. STUDY THE RESULTS

This phase is responsible for the

monitoring and evaluation of the

change.

If the problem has not been solved

appropriately, then some of the phases

will be repeated again.




6. STANDARDIZE THE SOLUTION.

Once the solution is accepted by the

team, it must be institutionalize by

positive control of the process, process

certification, and operator

certification.




7. PLAN FOR THE FUTURE.

The phase is responsible for continuous

process improvement.




BRAINSTORMING

•To encourage creativity.

•To obtain many ideas about a topic.

•Freedom expression of ideas.

•Some of them will be no useful.

•They will be discussed.

TEAMWORK TECHNIQUES


BRAINSTORMING: Use

• Problem solving.

• To identify problems causes.

• To identify provisional measures.

• To identify appropriate solutions.

• To obtain innovative ideas emerging from improvement groups.

Teamwork techniques


Teamwork techniques

BRAINSTORMING: Rules

•Small groups (3-8).

•The group has a leader.

•People in the group has to know and to understand the discussion subject.

•The group accepts ideas from anyone of the members without criticism.

•Meeting length is fixed.


Teamwork techniques

BRAINSTORMING: Phases

1. Subject definition: Meeting starts and objectives are explained.

2. Reflection: Some time is taken to think about the subject.

3. Ideas expression and exposition: Leader asks for ideas and write-down them.

4. Analysis and ideas selection: Leader starts debate to select the most accurate ideas concerning to the subject.


Teamwork techniques

AFFINITY DIAGRAM

It is a way for organizing information.

It helps to group together those elements

which are related in a natural way. (chunking

information)

It is a creative process. The team produces a

classification by mean of the consensus.


AFFINITY DIAGRAM : Use

• For complex or incomprehensible

problems.

• Unorganized problems.

• Problems involving many people.

• Problems requiring key point

identification.

Teamwork techniques


AFFINITY DIAGRAM: Phases

1. To set the problem.

2. To establish 5-10 people groups.

3. To carry out a brainstorming and to write-

down each one in a post-it.

4. To stick post-it in a blackboard.

Teamwork techniques


AFFINITY DIAGRAM : Phases

5. To group similar pos-it.

6. To name each group and to write down an

explicative text.

6. To draw the affinity diagram.

7. To write a complete document with text

corresponding to each one of the groups.

Teamwork techniques


Teamwork techniques

CATCHBALL

This tool was developed in Japan to encourage participation.

The main goal is to involve employees in finding out:

•Problem solutions

•Good opportunities to improve the future.


Teamwork techniques

CATCHBALL

1. To throw: Someone throws an idea.

2. To catch and to think about: Everybody in the group thinks about it and tries to understand it.

3. To improve: Somebody else says an improvement for the idea.

4. To throw again: Te improved idea is thrown to the group and the cycle starts again.


• Check sheet

• Histogram

• Pareto Diagram

• Diagram of Dispersion

• Control chart

• Cause-and-Effect Diagram

• Process Flow Diagram

The 7 quality tools[Kaoru Ishikawa]


The main purpose is to ensure that data are

collected carefully and accurately by

operating personnel.

Data must be collected in such a manner

that they can be quickly and easily used and

analyzed.

Check sheet


They are designed as a table or diagram.

They catch, organize or classify data.

They are used to:

•Solve problems.

•To start control process, improvement

process.

•To analyze and to interpret information.

Check sheet


It is a very well known tool. It is a frequency diagram. Vertical bars represent the frequency of a continuous variable. Each one of the bars is an interval or a class.

They can be used to analyze data distribution, and to evaluate the results of implementing improvement actions.

Histogram


Histogram

Biased distribution

Gauss / bell distribution Bimodal distribution


Diagram 80 – 20

It is very well known that:

“20% of causes are the origin of the 80% of

effects”

This fact can be enounced in quality as

follows:

“80% of defects are caused by the 20% of

processes”

Pareto’s diagram


It is a very special bars diagram. In this

case, frequencies are ordered in a

decreasing order.

This representation permits to identify

main factors related to a problem.

So that, we can quickly act to solve

problems.

Pareto’s diagram


Pareto’s diagram

It is a very powerful tool to:

•Identify the most important and serious

problems.

•Study problem causes to remove them.

•Decide the objective of an improvement

proposal.

•Predict improvement effectiveness.


Pareto’s diagram

Error

class

#

Errors

Total % Accumu-

lated %

D 35 50% 50%

B 17 24% 74%

E 8 11% 85%

A 7 10% 95%

C 3 4% 100%

TOTAL 70 100%

10

20

30

40

50

60

70

100%

80%

60%

40%

20%

FewImportant

ManyTrivial

D B E A C


It is a correlation diagram. It permits to analyze if there is some relation between two data groups (variables).

It can be used to:

•Verify if there is a relation between two process variables.

•Estimate values of a variable hard to measure using other correlated variable.

•Show cause / effect relation between two variables.

Diagram of Dispersion


They are linear graphs to study, manage and

evaluate processes stability through the

time depending on a variable value, and

usually, at a glance.

Upper and lower bounds are established and

they are used to determine if processes are

or not under control.

Control charts


It is also known as fishbone diagram or

Ishikawa diagram.

It is used to represent and to study the

relationship among one effect and its

possible causes.

It is a way to determine the problem’ source

and how to effectively solve it.

Cause–and-Effect diagram


C&E diagram

It is a very powerful tool to:

•Identify true causes of a situation and

grouping them into categories.

•Summarize causes and effect of a process.

•Be favorable to critical thought.

•Analyze and solve problems in a systematic

way.




STEPS:

•To give a clear problem definition.

•To identify main factors (4 to 8).

•To determine causes and sub-causes associated to each one of the main factors.

•To select most likely causes and to classify and order them.

•To find out and to remove the root cause.


http://tecnicasdeinvestigacion.wordpress.com

/2009/03/18/diagramas-causa-efecto/


HEAD

Main bone Main bone

Main boneMain bone

bone

Minor bone

spine

http://tecnicasdeinvestigacion.wordpress.com/


http://tecnicasdeinvestigacion.wordpress.com

/2009/03/18/diagramas-causa-efecto/


http://tecnicasdeinvestigacion.wordpress.com/


These diagrams show the flow of the

product or service as it moves through

the various processing operations.

The diagram makes it easy to visualize

the entire system, identify potential

trouble spots, and locate control

activities.

Process flow diagram

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