Reliability

Reliability
See also
Evaluation criteria Quality loss function Descriptive model Experimental error Designed quality Visual inspection Capacity analysis Fitness for use Types of validation

Reliability is defined as the probability of the event, which lies in the fact that the product used in certain circumstances will keep the ability to meet the requirements within a specified period of time of use. Reliability is also sometimes interpreted as a quality stretched in time: "reliable quality". Quality, however, is the overriding concept, because reliability does not guarantee a high level of quality.

Reliability in research: see below.

Definitions of Reliability

The most common definitions related to reliability include:

• Damage - a loss of ability of product to meet requirements.
• Readiness - the ability of an object to fulfil certain requirements, under the circumstances at the time.
• Maintainability - the ability to maintain ability meet the specific requirements under the given conditions of use
• Provision of service - the ability of an organization that deals with the service to provide the resources needed to handle the object.

Reliability meaning

Reliability is variously interpreted and perceived by different people, depending on function. For example:

Reliability in design

Reliability concerns the readiness of the product to perform certain functions of this product in a time when the user needs it. The readiness of product to meet the specific requirements is influenced by:

• resistance to damages,
• maintainability, and
• provision of the means to required for usage.

Reliability for entrepreneurs

For the entrepreneur reliability determines the competitiveness of the product and allows the safe use of the product. According to the entrepreneurs, product is more reliable when it reduces the value of cost of processes, which is associated with a lower cost of production.

Reliability as confidence

Product reliability is associated with confidence in the product. It is related to:

• safety,
• service,
• small costs associated with the acquisition and possession, and
• product usage that is not disturbed by damages.

Reliability and durability

The terms of durability and reliability are often equated with each other. However, these are two different concepts. Durability determines how long the product did not show significant loss of the initial level of quality, that is, how long will it match the requirements under the specified conditions of use or storage. While reliability determines probability of meeting your requirements in time and under specified conditions of use.

Reliability in research

Reliability in research is a way of assessing the quality of the measurement procedure used to collect data in a scientific research. In order for the results from a study to be considered valid, the measurement procedure must first be reliable.

Types of reliability

There are three main types of reliability:

• related to successive measurement,
• related to simultaneous measurement by more than one researcher,
• related to single measurement point.

Those types are discussed in detail here.

Data reliability

Data reliability is the accuracy and completeness of computer-processed data, given the use they are intended for. In order to be reliable, data must be complete, accurate and consistent.

Reliability and validity

Validity is a term used in statistics and scientific research to describe:

• accuracy - the degree to which chosen method measures what it is supposed to measure,
• construct validity - the degree to which practical test measure what theory says they should do,
• content validity - systematic examination of method to unveil whether it covers all important areas of the phenomenon it is supposed to evaluate.
• criterion validity - evaluation of validity of the criterion against other parts of the method which are held to be valid.

References

• Reliability in research
• Gertsbakh I.B (1988) Statistical reliability theory, Oakland University, New York:Marcel Dekker Inc.
• Krippendorff K. (1970) Estimating the reliability, systematic error and random error of interval data, Educational and Psychological Measurement, 30, 61-70

Author: Teresa Śpiewla, Slawomir Wawak