- Published
- 8 October 2026
- Last reviewed
- 8 October 2026
How to use this glossary
Use this glossary before a process workshop or small improvement trial. Statistical tools need suitable data and assumptions; short definitions do not replace training or establish certification competence.
Browse the alphabetical term index below. Select a term to jump to its definition, example and common mistake. Use the return link after each entry to browse again. You can also use your browser’s Find command to locate a word on this page. Definitions are original RDE plain-language explanations. All examples are fictional teaching scenarios.
Term index
12 terms, listed alphabetically.
- Baseline
- Bottleneck
- Control chart
- Control limits
- Cycle time
- Defect
- DMAIC
- Lean
- Processing time
- Root cause
- Specification limits
- Variation
Definitions and practical examples
Baseline
Meaning: A recorded starting level used to compare later process performance.
Example: A team measures request completion times before testing a new approval sequence.
Common mistake to avoid: Use consistent definitions and comparable observations before claiming improvement.
Bottleneck
Meaning: A constraint that limits the rate at which a process can produce output.
Example: Completed requests accumulate before the one approval step with limited capacity.
Common mistake to avoid: A visible queue suggests a constraint but does not prove its cause.
Control chart
Meaning: A time-ordered chart with statistically derived limits for monitoring process variation.
Example: A team charts weekly process results using a method appropriate to the data.
Common mistake to avoid: A simple trend chart without control limits is not a control chart.
Control limits
Meaning: Statistical boundaries describing expected variation for a process under a specified chart method.
Example: The team calculates limits from a suitable baseline and investigates special signals.
Common mistake to avoid: These are not customer requirements or arbitrary targets.
Cycle time
Meaning: Elapsed duration of one defined work cycle, using stated start and finish points.
Example: A request takes two days from receipt to completion, including time waiting.
Common mistake to avoid: Here the service cycle includes waiting. Manufacturing and other contexts may distinguish cycle time from lead time; define boundaries and units before comparing results.
Defect
Meaning: Failure to meet an agreed requirement or specification.
Example: A completed record lacks a mandatory approval reference.
Common mistake to avoid: Define the requirement first; not every difference is a defect.
DMAIC
Meaning: A structured improvement sequence: Define, Measure, Analyse, Improve and Control.
Example: A team defines a delay problem, measures it, investigates causes and tests a change.
Common mistake to avoid: Do not jump from a complaint to a solution without checking the problem and data.
Lean
Meaning: An approach focused on customer value, flow and reducing unnecessary work.
Example: A team removes repeated copying that adds no useful information for the customer.
Common mistake to avoid: Reducing headcount is not a complete definition of Lean.
Processing time
Meaning: Time actively spent working on an item within a defined process.
Example: An administrator handles a request for ten minutes, although it waits overnight.
Common mistake to avoid: Keep active time separate from total elapsed time.
Root cause
Meaning: An underlying cause supported by investigation and relevant evidence.
Example: Missing request details repeatedly trigger rework; the team tests a clearer input form.
Common mistake to avoid: The first plausible explanation is a hypothesis, not a confirmed root cause.
Specification limits
Meaning: Required boundaries for a product or process result.
Example: A service agreement defines a maximum acceptable completion time.
Common mistake to avoid: A specification can be missed even when the process is statistically stable.
Variation
Meaning: Differences observed in process results over time or between items.
Example: Similar requests take different amounts of time because conditions vary.
Common mistake to avoid: Do not assume every difference needs the same response; investigate its pattern and context.
A distinction worth keeping clear
Control limits describe expected variation derived from process data. Specification limits describe required performance. A process can be stable yet consistently fail customer requirements. Do not swap these two types of limit in a chart.
Practise using the terms
A team measures elapsed request time and records active handling time separately. It finds that most elapsed time occurs while requests wait for approval. Which measure is cycle time, which is processing time, and what should the team investigate before changing the process? Write your answer in your own notes before reading the explanation. No answer is submitted or stored by this page.
Suggested answer and explanation
Cycle time is elapsed time across the defined process boundary. Processing time is time actively spent doing the work. The team should examine queue conditions, arrival patterns, approval capacity and request completeness before concluding that approval alone is the root cause.
Sources and scope
The sources below support the terminology and relevant context. The definitions, examples, cautions and practice tasks on this page are original RDE teaching material, not verbatim extracts or a replacement for an official standard or certification syllabus. Reviewed 8 October 2026. Author: Jefferson Otonbara Imgbi.
Cover image: AI-generated illustrative scene created specifically for this resource.