Much of what we think of as Quality Control derived from a scientific discipline called

Statistical Process Control. Possibly the most honoured early practitioner / designer in that

field was a man named Walter A. Shewhart (1891-1967), often called the father of statistical

quality control, whose work at the Inspection Engineering Department of the Western

Electric Company at Hawthorne (near Chicago, IL, in the 20s and 30s set the stage for what

is often called Continuous Process Improvement. He worked there on statistical tools to

examine when a corrective action must be applied to a process. The control chart techniques

which he developed have been widely adopted. During the 1990s, Shewhart’s genius was re-

discovered by a third generation of managers, naming it the "Six Sigma" approach. William

Edwards Deming (who often gave Shewhart the credit for his own successes) is almost

certainly the most well-known of the Quality Gurus. From June–August 1950, Deming

trained hundreds of engineers, managers, and scholars in statistical process control (SPC) and

concepts of quality. He also conducted at least one session for top management.(The list

includes top Japanese industrialists the likes of Akio Morita, the cofounder of Sony Corp)[13]

Deming's message to Japan's chief executives: improving quality will reduce expenses while

increasing productivity and market share. He codified his learnings/expertise into 14

Managing quality on your project means that you must first understand the specific quality

expectations of your customer and then put a proactive plan in place to meet those

expectations. The "proactive plan" contains a number of elements -- the most important of

which are the quality control and quality assurance activities that need to be performed.

The QA team's job is to see that standards, processes, and policies (or other

governing/guiding "writ") are in place and carried out; to recommend and implement

improvements to them, and to ensure that the people that need to know about them know

about them. QA "audits" or "reviews" are intended to determine the efficacy of these "writs."

It's often easier to understand QA by an example: In one place (a large company with large

projects) QA's role might be to help project managers plan their projects -- so that the

projects follow certain organizational procedures; so that they include the required artifacts,

events, and milestones; and so that the projects know what is expected of them and when in

terms of reports, reviews, and documentation. As the project progressed, QA would conduct

"checkpoints" along the way to see where the project may be developing risks, for example

either by progressing beyond where they've got authorization to go, or where they may have

need to escalate issues to management. These checkpoints would also be an opportunity to

ensure that people who need to be involved are involved at the right times.

As per American National Standard (ANSI/ASQC A8402-1994), Quality Control (QC) refers

to all the planned and systematic activities implemented within the quality system, and

demonstrated as needed, to provide adequate confidence that an entity will fulfil requirements

for quality. QC, then, could be called a system of routine technical activities, to measure and

control the quality of the inventory as it is being developed. The QC system is designed to:

(i) Provide routine and consistent checks to ensure data integrity, correctness, and

completeness;

(ii) Identify and address errors and omissions;

(iii) Document and archive inventory material and record all QC activities.

QC activities include general methods such as accuracy checks on data acquisition and

calculations and the use of approved standardised procedures for emission calculations,

measurements, estimating uncertainties, archiving information and reporting. Higher tier QC

activities include technical reviews of source categories, activity and emission factor data,

and methods.

In order to implement an effective QC program, an enterprise must first decide which specific

standards the product or service must meet. Then the extent of QC actions must be

determined (for example, the percentage of units to be tested from each lot). Next, real-world

data must be collected (for example, the percentage of units that fail) and the results reported

to management personnel. After this, corrective action must be decided upon and taken (for

example, defective units must be repaired or rejected and poor service repeated at no charge

until the customer is satisfied). If too many unit failures or instances of poor service occur, a

plan must be devised to improve the production or service process and then that plan must be

put into action. Finally, the QC process must be ongoing to ensure that remedial efforts, if

required, have produced satisfactory results and to immediately detect recurrences or new

instances of trouble.

Sampling plans in the form of published standards are used in industry world-wide as a

means of assisting quality control personnel to decide whether to accept or reject lots of

product presented for inspection. There are a number of standards available. Commonly used

standards are ANSI/ASQ Z1.4 (replacing MIL-STD-105E) and ISO 2859-1 for inspection by

attributes and ANSI/ASQZ1.9 and ISO 3951 for inspection by variables.

The standards provide inspectors with information on the size of sample to be selected and a

set of rules and procedures, related to the AQL (acceptable quality limit), which enables the

inspector, having examined the sample, to decide on the acceptance or rejection of the lot.

The sampling standards provide organisations with an effective and cost efficient means of

selecting sample sizes and devising sampling plans. The switching rules, when correctly

used, provide for reduced sampling when incoming product is of consistently good quality,

thereby considerably reducing inspection costs, while also providing for more stringent tests

should quality levels decline. The variables sampling plans (e.g. ANSI/ASQ Z1.9) should be

more widely used, in circumstances where samples are examined by measurement, because

inspection by variables requires considerably smaller sample sizes, when compared to

inspecting the same characteristic by attributes. Emphasis will be placed in this training

course on the correct use of the switching rules and selection of the appropriate standard.

Clearly, there are marked differences between quality guarantee and quality control.

Assurance of quality is a set of preventive activities, which are focused on processes whereas

quality control is a detection activity, which is focused on detecting the defects once the

product is manufactured. Assurance defines the standards to be followed in order to meet the

customer requirements whereas quality control ensures that these defined standards are

followed at every step. This is done by conducting various tests and checks. Based on these

tests and checks, the quality control prepares regular reports that act as an input to the

assurance of quality department which then reviews the same and decides on the corrective

and preventive actions required in the processes.

Despite the differences in the definition of quality assurance and quality control, these terms

are often used interchangeably. But whatever you term it as, the importance of both cannot be

undermined. Quality guarantee department develops all the planning processes and

procedures that try to make sure that the products manufactured by the organization or the

service delivered by the organizations will always be of good quality. Despite all these, some

process parameters cannot be controlled and here is where quality control comes into picture.

They check the products or services for the defects that happen due to these parameters and

hence help quality control in achieving the overall objective of providing a defect-free

product or service to the customers. So whether you call it assurance or control, quality is the

goal.

Here's an example to drive home the point. Let's say a project manager asked the sponsor to

approve the Business Requirements Report. If you were the sponsor, how would you validate

that the business requirements seemed complete and correct?

One solution would be for you to actually review the document and the business

requirements. If you did that, you would be performing a quality control activity, since your

actions would be based on validating the deliverable itself.

However, let's say the document was thirty pages long and that you (as the sponsor) did not

have the expertise, the time, or the inclination to do a specific content review. In that case,

you wouldn't ask to review the document itself. Instead, you would ask the project manager

to describe the process used to create the document. Let's say you received the following

reply.

Project manager - "I gathered eight of your major users in a facilitated session. After the

meeting, I documented the requirements and asked the group for their feedback,

modifications, etc. I then took these updated requirements to representatives from the Legal,

Finance, Manufacturing and Purchasing groups and they added requirements that were

needed to support company standards. We then had a meeting with the four managers in your

area that are most impacted by this system. These managers added a few more requirements.

I then asked your four managers to sign off on the requirements and you can see their

signatures on the last page."