Quality is one of the modern project constraints which leads the project management processes and activates. There are 3 processes of quality management throughout the project lifecycle. These are-
- Plan quality management
- Perform quality assurance
- Control quality
Each of the 3 processes have their own tools, but there are some tools that can be used in all the 3 processes. These 7 basic quality tools are examples of shareable tools :
1- Flow Chart :- It is a graphical description of workflow steps. So it can describe the steps of any process through graphical symbols which are connected to each other by paths that represent the direction of the workflow. The symbols can be circles, rectangles, diamonds or any other shapes which must be predefined to make the flowchart easy for understanding.We begin the flowchart by the start node, which is often represented as a circle shape. Then we represent each action or step we do by rectangle shape. When we want to make a decision or a test that will give more than one result, each result will direct us to a different path with a different action. Flowcharts are very useful when we want to make a correction for any process. It helps us eliminate the redundancy and unuseful work steps. Also, it is very useful when we use it for creating the project statement of work.
2- Pareto Diagram :- It is a special vertical chart that is divided into categories which show all possible probabilities or events that can occur. Categories are ordered by the frequency of each category from high frequency on the left side of the vertical axis to low frequency on the right side of it. Pareto depends on the rule of 80/20, which proves that 80/100 of problems comes from 20/100 of causes. So when we know that 20/100 of causes and give more attention and resources to avoid them, we will solve 80/100 of errors and problems. So Pareto Diagram is very useful when we use it with cause and effect diagram (also called Ishikawa or fishbone). The below example shows Pareto Diagram for the reasons that lead to delay in a software project.
3- Histogram : It is a tool for showing the central tendency, statistical distribution and dispersion of a given set of measurements that will be shown on a vertical bar chart . it is very useful when we want to know which categories have a larger frequency. We can use it in many applications such as- defining the resources that will perform the project work by using Resource Histogram which shown below
We can do the same thing with one resource in a timely manner such as dividing the categories by months and defining the number of one resource such as senior developer via each month of the project lifecycle.
4- Cause and Effect Diagram (Ishikawa or Fishbone):
It is a diagram that represents the cause and effect as a fishbone. Its head represents the problem or objective and the body represents the causes of the problem or the actions that should be performed to reach the goal or objective at the head of the fishbone. When we find a problem with any process such as a process variation or an increasing number of defects, we can use the fishbone to find the source of problem. Each resource can also be divided into a number of resources, till we reach the original resources of the problem. The Fishbone problem statement often comes from the Control Chart when its measurements point to a problem in the process stability. The following diagram shows the cause and effect diagram for the delay of software projects
5- Checksheets (Tally sheets) :-
Check sheet is a sheet that contains items of inspections and tests and the attribute that each test can result in. The acceptance criteria of each test must be listed on the sheet to be a guide for determining if the inspected item of the sample such as- a piece of code in the software project has passed a test item (such as a unit test). Then we gather the frequencies of each defect and represent it in Pareto Chart.
6- Scatter Diagram :
Scatter diagram (called also Correlation Diagram) is a diagram represented by two axes X and Y. So any measurement or data shown in Scatter Diagram is represented by a pair of (X,Y). The correlation between x and y shown is based on the rule that Y is dependent on X but X is not dependent on Y. So there are many types of correlations such as- positive correlation (proportional), negative correlation (Inverse) or pattern of no correlation (Zero Correlation). An example of positive correlation is- the weight of the human and its relation to his age (between one year and 40 ). We find that the weight of the human depends on and is affected by age (increase in age will lead to increase in weight but the reverse is incorrect). So we will consider the age is X axis and the weight is Y axis. In a negative correlation, when X is increased, Y decreases.
7- Control Chart:
When we want to determine if a process is stable or not, we use a control chart. It consists of-
- Upper Specification Limits (USL) and Lower Specification Limits (LSL) which come from specification
- Upper Control Limits(UCL) and Lower Control Limits (LCL) which come from statistical calculation +_3 standard deviation above and below mean
- Mean which equals UCL+LCL/2
The process is considered unstable if one point exceeds the UCL or LCL or seven consecutive points are above or below the mean.
When we ensure that the process is unstable, we perform a corrective action and monitor the result of these actions to measure its effect on the process stability.
So these 7 tools are very useful and can be used throughout the project lifecycle to plan and maintain the quality associated activities.