Database organization method that links files together as required. Relationships between files are created by comparing data such as account numbers and names. A relational system can take any two or more files and generate a new file from the records that meet the matching criteria. Routine queries often involve more than one data file; e.g., a customer tile and an order file can be linked in order to ask a question that relates to information in both tiles, such as the names of the customers that purchased a particular product. Contrast with network database, flat tile

Method is a technique developed to clarify intertwined causal relationships in a complex situation in order to find an appropriate solution. It is typically represented graphically as squared ellipses (concepts) connected by directed lines (arrowheads show direction). The directed lines represent causal relations between the concepts

The probability that an item will continue to function at customer expectation levels at a measurement point, under specified environmental and duty cycle conditions / Or / The ability of a system or component to perform its required functions under stated conditions for a specified period of time. See: software reliability / Or / the probability of a product performing its intended function under stated conditions without failure for a given period of time

The process of determining the achieved level of reliability for an existing system or system component

Taken on non-conforming product so that the product will fulfill the intended usage, although the product may not conform to the original requirements. [Also see Regrade/Rework] 

(1) A condition or capability needed by a user to solve a problem or achieve an objective (2) A condition or capability that must be met or possessed by a system or system component to satisfy a contract, standard. specification, or other formally imposed documents. (3) A documented representation of a condition or capability as in (1) or (2). See: design requirement, functional requirement, implementation requirement, interface requirement, performance requirement, physical requirement

(1) The process of studying user needs to arrive at a definition of a system, hardware, or software requirements. (2) The process of studying and refining system, hardware, or software requirements. See: prototyping, software engineering

The period of time in the software life cycle during which the requirements, such as functional and performance capabilities for a software product, are defined and documented

Critical and exhaustive investigation or experimentation having for its aim the revision of accepted conclusions in the light of newly discovered facts

Those items necessary for a team to understand a problem and implement solutions; also, the time to work on solutions, access to manufacturing engineers, etc

Relative to software changes, revalidation means validating the change itself, assessing the nature of the change to determine potential ripple effects, and performing the necessary regression testing

A process or meeting during which a work product or set of work products, is presented to project personnel, managers, users, customers, or other interested parties for comment or approval. Types include code review, design review, formal qualification review, requirements review, test readiness review. Contrast with audit, inspection. See: static analysis

A term used to convey the concept that it is beneficial and more cost-effective to take the necessary steps up front to ensure a product or service meets its requirements than to provide a product or service that will need rework or not meet customers needs. In other words, an organization should engage in defect prevention rather than defect detection

A measure of the probability and severity of undesired effects. Often taken as the simple product of probability and consequence

The condition or state in which a response parameter exhibits hermetically to external cause of a nonrandom nature; i.e., impervious to perturbing influence

The condition of a product or process design that remains relatively stable with a minimum of variation even though factors that influence operations or usage, such as environment and wear, are constantly changing

(defect-based)--the probability of being able to pass a unit of product or service through the entire process defect-free

1) SPC: A consecutive number of points consistently increasing or decreasing. 2) Production: The production of a specified number of sequential units

A simple graphic representation of a characteristic of a process / Or / Also known as a line chart, or line graph. A chart that plots data over time, allowing you to identify trends and anomalies / Or / shows the history and pattern of variation. It is helpful to indicate on the chart whether up is good or down is good. This tool is used at the beginning of the change process to see what the problems are. It is used at the end (check) part of the change process to see whether the change has resulted in a permanent improvement

Freedom from those conditions that can cause death, injury, occupational illness, or damage to or loss of equipment or property, or damage to the environment

A term applied to a condition, event, operation. process or item of whose proper recognition, control, performance or tolerance is essential to safe system operation or use; e.g., safety critical function, safety critical path, safety critical component

Those computer software components and units whose errors can result in a potential hazard, or loss of predictability or control of a system

A subset of a population used to represent the population in statistical analysis. Samples are almost always random, which means that all individuals in the population are equally likely to be chosen for the sample / Or / One or more observations drawn from a larger collection of observations or universe (population)

Control chart in which the standard deviation of the subgroup is tracked to determine the variation within a process over time. Sample standard deviation charts are usually paired with average charts for complete analysis

Is used to interpret data by graphically displaying the relationship between two variables / Or / show the pattern of relationship between to variables that are thought to be related. For example is their a relationship between out side temperature and cases of the common cold? As temperatures drop, do colds increase. The closer the points hug a diagonal line the more closely there is a one to one relationship / Or / a graphical technique to analyze the relationship between two variables. Two sets of data are plotted on a graph, with the y axis being used for the variable to be predicted and the x axis being used for the variable to make the prediction. The graph will show possible relationships (although two variables might appear to be related, they might not be: those who know most about the variables must make that evaluation). The scatter diagram is one of the seven tools of quality / Or / Charts which allow the study of correlation, e.g., the relationship between two variables

A tool that studies the possible relationship between two variables expressed on the x-axis and y-axis of a graph. The direction and density of the points plotted will indicate various relationships or a lack of any relationship between the variables

Quality improvement tools that include the histogram, Pareto chart, check sheet, control chart, cause-and-effect diagram, flowchart, and scatter diagram / Or / tools that help organizations understand their processes in order to improve them. The tools are the cause-and-effect diagram, check sheet, control chart, flowchart, histogram, Pareto chart, and scatter diagram (see individual entries)

Referred to as the father of statistical quality control because he brought together the discipline of statistics, engineering, and economics. He described the basic principles of this new discipline in his book Economic Control of Quality of Manufactured Product. Shewhart, ASQ’s first Honorary member, was best known for creating the control chart. Shewhart worked for Western Electric and AT&T Bell Telephone Laboratories in addition to lecturing and consulting on quality control

An unintended alteration of a program's behavior caused by a change in ore part of the program, without taking into account the effect the change has on another part of the program. See: regression analysis and testing

Is a statistical unit of measure which reflects process capability. The sigma scale of measure is perfectly correlated to such characteristics as defects per unit, parts per million defective, and the probability of a failure/error

Product and process characteristics designated by the customer, including governmental regulatory and safety, and/or selected by the supplier through knowledge of the product and process

A software V&V task to simulate critical tasks of the software or system environment to analyze logical or performance characteristics that would not be practical to analyze manually