Quality Assurance (QA) is a way of preventing mistakes and defects in manufactured products and
avoiding problems when delivering products or services to customers; which ISO 9000 defines as part
of quality management focused on providing confidence that quality requirements will be fulfilled.
The terms quality assurance and quality control are often used interchangeably to refer to ways of ensuring the quality of a service or product. Quality assurance comprises administrative and procedural activities implemented in a quality system so that requirements and goals for a product, service or activity will be fulfilled. It is the systematic measurement, comparison with a standard, monitoring of
processes and an associated feedback loop that confers error prevention. This can be contrasted
with quality control, which is focused on process output.

Quality assurance includes two principles: Fit for purpose (the product should be suitable for the intended purpose); and right first time (mistakes should be eliminated). QA includes management of the quality of raw materials, assemblies, products and components, services related to production, and management, production and inspection processes. The two principles also manifest before the background of developing (engineering) a novel technical product: The task of engineering is to make it work once, while the task of quality assurance is to make it work all the time. Historically, defining what suitable product or service quality means has been a more difficult process, determined in many ways, from the subjective user-based approach that contains the different weights that individuals normally attach to quality characteristics, to the value-based approach which finds consumers linking quality to price and making overall conclusions of quality based on such a relationship.
To make the product more reliable it should go under various steps for testing known as Approaches.

Approaches:
Failure Testing
It is valuable to failure test or stress test a complete consumer product. In mechanical terms this is the
operation of a product until it fails, often under stresses such as increasing vibration, temperature,
and humidity. This may expose many unanticipated weaknesses in the product, and the data is used to
drive engineering and manufacturing process improvements. Often quite simple changes can dramatically improve product service, such as changing to mold-resistant paint or adding lock-
washer placement to the training for new assembly personnel.

Statistical control
Statistical control is based on analyses of objective and subjective data. Many organizations
use statistical process control as a tool in any quality improvement effort to track quality data. Any
product can be statistically charted as long as they have a common cause variance or special cause
variance to track.

Total quality management
The quality of products is dependent upon that of the participating constituents, some of which are
sustainable and effectively controlled while others are not. The process which are managed with QA
pertain to total quality management.
For instance, the parameters for a pressure vessel should cover not only the material
and dimensions but operating ,environmental,  safety,  reliability  and  maintainability  requirements.

Models and standards
ISO 17025 is an international standard that specifies the general requirements for the competence to
carry out tests and or calibrations. Management system refers to the organization's structure for
managing its processes or activities that transform inputs of resources into a product or service which
meets the organization's objectives, such as satisfying the customer's quality requirements, complying with regulations, or meeting environmental objectives. WHO has developed several tools and offers training courses for quality assurance in public health laboratories.
The Capability Maturity Model Integration (CMMI) model is widely used to implement Process and
Product Quality Assurance (PPQA) in an organization. The CMMI maturity levels can be divided into 5
steps, which a company can achieve by performing specific activities within the organization.

Company quality
During the 1980s, the concept of company quality with the focus on management and It was
considered that, if all departments approached quality with an open mind, success was possible if
management led the quality improvement process.
1. Elements such as controls, job management, adequate processes, performance and integrity
criteria and identification of records
2. Competence such as knowledge, skills, experiences, qualifications
3. Soft elements, such as personnel integrity, confidence, organizational culture,  motivation, team
spirit and quality relationships
4. Infrastructure (as it enhances or limits functionality)
The quality of the outputs is at risk if any of these aspects is deficient.
QA is not limited to manufacturing, and can be applied to any business or non-business activity,
including: design, consulting, banking, insurance, computer software development, retailing,
investment, transportation, education, and translation.
It comprises a quality improvement process, which is generic in the sense that it can be applied to any of
these activities and it establishes a behavior pattern, which supports the achievement of quality.
This in turn is supported by quality management practices which can include a number of business
systems and which are usually specific to the activities of the business unit concerned.
As our organization is concerned, it has always been committed in the quality service. The members of
this company have studied all the aspects in depth and have tried to apply in practical teaching along
with the assurance of quality product.
Though in the context of Nepal it is not so easy to apply all the above principles or aspects of quality
control, we are back in quality raw materials, proper engineering, competent staffs, appropriate acts
and its implementation etc. Still we are moving some steps ahead to maintain all these. Despite all the
drawbacks, we are not counting them but trying to overcome them with our limited resources, acts and
even the proper thought of quality.