CSSYB flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Six Sigma Definition

A disciplined, data-driven methodology that reduces process variation and defects, aiming for no more than 3.4 defects per million opportunities.

Y = f(X)

The principle that process outputs (Y) are determined by process inputs (X); improvement comes from identifying and controlling the key X variables.

DMAIC Acronym

Define, Measure, Analyze, Improve, Control: the five-phase roadmap used to improve existing processes and sustain the resulting gains.

Rolled Throughput Yield

The probability that a unit passes every process step without a defect; calculated as the product of each step's individual yield, or e raised to negative DPU.

Cost of Poor Quality

Costs associated with producing defective output, including scrap, rework, warranty, and inspection; reducing these costs is a primary financial justification for Six Sigma projects.

SIPOC Diagram

A high-level process map showing Suppliers, Inputs, Process, Outputs, and Customers; it defines project boundaries and helps the team agree on scope.

SMART Goal

A project goal that is Specific, Measurable, Achievable, Relevant, and Time-bound; it states the metric, baseline, target, and deadline without prescribing a solution.

Voice of Customer

Customer needs and expectations gathered through surveys, interviews, complaints, and observation; these are translated into Critical to Quality requirements for the project.

Project Charter

A formal document authorizing the project; it defines the problem, business case, goal, scope, team, milestones, and metrics, and is approved by the project sponsor.

Stakeholder Analysis

A tool that maps people or groups by power and interest so the team can plan communication and engagement; high-power, high-interest stakeholders require active management.

DPMO

Defects per million opportunities; calculated as defects divided by units times opportunities, then multiplied by one million, and used to compare processes.

Cp and Cpk

Process capability indices: Cp compares specification width to process spread, while Cpk accounts for centering; Cpk of 1.33 or higher is generally acceptable.

Gage R&R

A measurement system study that estimates repeatability and reproducibility; results below 10% of tolerance are acceptable, 10-30% may be conditionally acceptable, and above 30% is unacceptable.

Continuous vs Discrete Data

Continuous data can take any value within a range and supports powerful tests; discrete data counts categories or occurrences and includes nominal and ordinal scales.

DPU

Defects per unit; the average number of defects found per item, calculated as total defects divided by total units, and used to compute rolled throughput yield.

Data Collection Plan

A document specifying what data to collect, operational definitions, sampling method, frequency, location, and responsible person, ensuring consistent and valid measurement before analysis begins.

P-Value Rule

If the p-value is less than the chosen significance level (usually 0.05), reject the null hypothesis; otherwise, fail to reject it and consider the result not statistically significant.

Type I Error

Also called alpha, it is the probability of rejecting a true null hypothesis, equivalent to a false positive; lowering alpha reduces this risk but raises Type II error.

Fishbone Diagram

A cause-and-effect tool that organizes potential root causes into categories such as manpower, machine, material, method, measurement, and environment to guide team brainstorming.

FMEA RPN

Risk Priority Number equals Severity times Occurrence times Detection; higher scores indicate higher-priority failure modes for corrective action, and the RPN is recalculated after improvements.

Correlation Coefficient

A value between -1 and +1 that measures the strength and direction of a linear relationship between two variables; it does not by itself prove causation.

ANOVA

Analysis of variance; a hypothesis test comparing the means of three or more groups by analyzing between-group and within-group variation to determine if differences are statistically significant.

Poka-Yoke

Error-proofing designed into a process to prevent mistakes from occurring or to detect them immediately; it is preferred over inspection because it stops defects at the source.

PDCA Cycle

Plan, Do, Check, Act; an iterative improvement cycle used to pilot changes, verify results, and standardize successful solutions before broader implementation.

5S Workplace Organization

Sort, Set in order, Shine, Standardize, and Sustain; a Lean method that creates a clean, organized workplace to reduce waste, errors, and search time.

Design of Experiments

A structured method that deliberately varies factors at set levels to identify significant effects and interactions, allowing efficient optimization of process settings.

Impact-Effort Matrix

A prioritization tool plotting solutions by expected impact versus implementation effort; high-impact, low-effort options are typically selected first for quick wins.

Control Chart Limits

Control limits are calculated from process data at plus or minus three standard deviations from the mean; they are not specification limits and represent the voice of the process.

Control Plan

A document listing the process characteristics to monitor, the measurement method, sampling frequency, control limits, owner, and the reaction plan when out-of-control conditions occur.

Special Cause Variation

Unusual variation from assignable causes that is not inherent in the process; it appears as points beyond control limits or nonrandom patterns and requires investigation.

Out-of-Control Action Plan

A predefined response specifying who does what when a control chart signals an out-of-control event, including containment, root cause investigation, and corrective action.

Standard Operating Procedure

A documented, approved work instruction that defines the standard method for a task; it supports sustainment by ensuring consistent execution after improvements are implemented.