DoE Flow Chart


We have seen that the DoE is a integral part of any QbD studies however, we seldom apply it properly during developmental stage. I have seen scientist afraid of using it because, they think that DoE means  more experiments. But in reality what I have seen that they end-up in doing more experiments than that suggested by DoE. To give you an idea, scientist would perform 40-50 experiments if they are investigating 4-5 variables whereas, DoE con do that job in 15-20 experiments. This is because, when DoE experiments proposes 15-20 experiments in a single go, it appears more for the developmental team. Other issue is that the lack of knowledge on how to exploit the DoE using fractional factorial designs, Plackett-Burma or D-optimal etc.

This article describes the flow diagram for conduction a successful DoE.

DoE Flow

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7QC Tools: Flow Chart, Know Your Process Thoroughly

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Picture52Rightly said by Deming, if we really want to improve our processes then there are two thing to be taken care of. Firstly, we must know our process to an extent that even if someone ask us in the middle of the night, it should come instantaneously from out mouth as if we have witnessed the process every day. Second most important thing is that we must have some measurement system to evaluate our process

Picture53We will deal with measurement in some other day, let’s talk about the process for the time being.

We all must have seen the organizational chart or an organogram that describes how the various departments are arranged within the organization. This chart is valuable in the sense that it enables us to visualize a complete organization, by means of a picture.


Similarly, every organization have business processes that give a pictorial view of the work flow within the organization for delivering a product/services. This helps employees to visualize the movement of men/material/services from department to another. This is also called as process map as it shows the sequence of events/task that are there in performing a given process.

For example: on a macro level, department ‘B’ in an organization has to do some work (adding value)  as shown below by the block diagram


But, for adding some value to the work, department ‘B’ must get some input from some other department say ‘A’ and once ‘B’ has added the value to the input received from ‘A’, it has produced some goods or services which becomes output from department ‘B’. This output in turn becomes input for some department ‘C’ or for an external customer. Same thing is depicted by the block diagram shown above where the flow of goods/services between the departments within the organization is shown.

For example, purchase of raw material by production can be represented by following flow diagram


This is called as flow diagram. The example given above is the flow diagram at macro level. Now let’s see the complete work flow or the flow chart at the sub-macro level for the process “order to dispatch” of some product.


In the above flow chart, we have tried to link the activities of various departments to fulfill the common goal of producing some goods/services for a customer. Point to be noted here is that, each block above represents a separate department hence, it represents a sub-process within that department which is required to be executed by that department in order to achieve the organizational goal of delivering the goods/services to the customer on time.

The micro level flow chart shows the entire sequence of events of a process by using some standard symbols with some specific meaning as shown below


Let’s look at the process of getting the raw material from the ware house for the production at micro level using flow chart


We can see that, it take almost 6 days to release a new batch of raw material for the production. In order to understand it further, the process of “analysis by QC” is investigated as shown below

We can see that the raw material reaches QC on second day, however the raw material is approved/rejected on on the sixth day! Why it is so? let’s get an answer from investigating the QC process


Now we can ask ourselves following questions

Why analysis starts at 3rd day when raw material is submitted on 2nd day itself? whether it is a manpower or machine constrain?

Why review of the QC would require a whole day?

If we can resolve the above issues, we can reduce the approval time by two days.

What we have done above is called as value stream mapping (VSM) of the process, thereby eliminating the non-value adding steps to increase the efficiency of the process.

Above example shows the power of flow chart/process mapping. But irony is that we seldom map the process and in absence of it, it is difficult to start any improvement program. This is because we need to have a baseline for the existing process in order to propose a improvement.

Other outcome of the flow chart is that we can make some decision about the root causes of a problem. Hence, flow chart in combination with fish-bone diagram is a very powerful tool to screen out most probable causes.

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