Introduction to QA/QC

1. 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:

2. (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

3. 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."