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Understand the metrics, models, and methods behind modern engineering. Clear definitions, practical examples, and a closer look at what the numbers actually mean.
Terms beginning with S
160 termsSoftware value stream
A software value stream is the sequence of activities and handoffs required to turn a software request into a usable outcome. It includes the work that creates new value and the recovery work required to restore or protect an existing service.
Engineering analyticsSource system
Source system identifies where measurement records originate.
Engineering analyticsSPACE framework
The SPACE framework is a multidimensional approach to understanding developer productivity across Satisfaction and well-being, Performance, Activity, Communication and collaboration, and Efficiency and flow.
Developer productivitySpan
Span is a timed unit of work within a trace with operation, timing, status, attributes, and events.
Reliability and observabilitySpan attribute
Span attribute is a key-value property attached to a span to provide searchable operation context.
Reliability and observabilitySpan event
Span event is a timestamped annotation attached to a span to record something during its lifetime.
Reliability and observabilitySpan ID
Span ID is the identifier for one span within a trace that distinguishes it from its parent and siblings.
Reliability and observabilitySparse autoencoder
Sparse autoencoder is a language-model concept about evaluation design and failure analysis. It names a mechanism, representation, training practice, or operational behavior that can change how an AI system processes input and produces output.
LLM fundamentalsSpecial cause variation
Special cause variation is a statistical or measurement concept used to describe, compare, or interpret engineering data. Its meaning depends on the unit of analysis, data-generating process, and question being asked.
Measurement and experimentationSpecial token
Special token is a language-model concept about representation and similarity. It names a mechanism, representation, prompting pattern, decoding control, or context behavior that can change how an AI system processes input and produces output.
LLM fundamentalsSpecialist queue
A specialist queue is a set of items that require capability available from only a small number of people or systems. It is a queue caused by constrained expertise rather than by total team capacity alone.
Flow and capacity planningSpecification by example
Specification by example is a software testing or test-design practice used to gather evidence about a defined risk, behavior, boundary, or operating condition. It makes the question under test explicit, identifies the inputs and observations that matter, and gives a team a repeatable basis for deciding whether the result is acceptable.
Code quality and technical debtSpeculative decoding
Speculative decoding is the serving concept concerned with speculative decoding during AI inference.
Inference performanceSpeculative generality
A code smell in which abstractions or extension points exist for hypothetical future needs.
Code quality and technical debtSpend attribution
Spend attribution is the mapping of AI spend to a product, team, workflow, user, or outcome. It gives teams a way to name, measure, or reason about an economic property of an AI workload without treating raw usage as proof of value.
Token costs and AI ROISpend limit
Spend limit is a model-routing or gateway concept used to manage policy enforcement for AI requests. It describes a distinct decision, control, interface, or observation point between an application and one or more model providers.
Model routing and gatewaysSpike testing
Spike testing is a software testing or test-design practice used to gather evidence about a defined risk, behavior, boundary, or operating condition. It makes the question under test explicit, identifies the inputs and observations that matter, and gives a team a repeatable basis for deciding whether the result is acceptable.
Code quality and technical debtSplit brain
Split brain is a reliability concept used to describe a specific condition, control, or decision in the operation of software services.
Reliability and observabilitySprint planning
Sprint planning is a concept used in software delivery planning to describe a condition, relationship, estimate, or decision about engineering work.
Flow and capacity planningSquash merge
Squash merge is a practical concept in a pull-request workflow that shapes how people examine, discuss, own, or integrate a proposed change.
Code reviewStacked pull requests
Stacked pull requests divide dependent work into a sequence of smaller changes that can be reviewed in order.
Code reviewStaged rollout
Staged rollout is a release engineering and DevOps concept for controlling how software changes are prepared, introduced, or understood.
DORA and DevOpsStakeholder alignment
Stakeholder alignment is a way to organize, support, or evaluate software work so that teams can make useful progress with less avoidable friction. It is most valuable when connected to a concrete outcome and the local conditions of the team using it.
Developer productivityStale review
Stale review is a practical concept in a pull-request workflow that shapes how people examine, discuss, own, or integrate a proposed change.
Code reviewStandard change
Standard change is a release engineering and DevOps concept for controlling how software changes are prepared, introduced, or understood.
DORA and DevOpsStandard error
Standard error is a statistical or measurement concept used to describe, compare, or interpret engineering data. Its meaning depends on the unit of analysis, data-generating process, and question being asked.
Measurement and experimentationStandard item
A standard item is work that follows the ordinary pull order, WIP policy, and service expectation of a workflow. It is distinguished from urgent, fixed-date, or other special classes of service.
Flow and capacity planningStartup probe
Startup probe is a reliability concept used to describe a specific condition, control, or decision in the operation of software services.
Reliability and observabilityState transition testing
State transition testing is a software testing or test-design practice used to gather evidence about a defined risk, behavior, boundary, or operating condition. It makes the question under test explicit, identifies the inputs and observations that matter, and gives a team a repeatable basis for deciding whether the result is acceptable.
Code quality and technical debtStatic batching
Static batching is the serving concept concerned with static batching during AI inference.
Inference performanceStatic routing
Static routing is a model-routing or gateway concept used to manage traffic selection for AI requests. It describes a distinct decision, control, interface, or observation point between an application and one or more model providers.
Model routing and gatewaysStatic-analysis false-positive rate
The share of reported static-analysis findings that reviewers determine do not represent actionable issues.
Code quality and technical debtStationarity
Stationarity is a statistical or measurement concept used to describe, compare, or interpret engineering data. Its meaning depends on the unit of analysis, data-generating process, and question being asked.
Measurement and experimentationStatistical power
Statistical power is a defined lens for examining AI system behavior with a stated task, evidence, and interpretation rule.
Evaluations and benchmarksStatistical process control
Statistical process control is a statistical or measurement concept used to describe, compare, or interpret engineering data. Its meaning depends on the unit of analysis, data-generating process, and question being asked.
Measurement and experimentationStep-back prompting
Step-back prompting is a language-model concept about generation behavior and sampling. It names a mechanism, representation, prompting pattern, decoding control, or context behavior that can change how an AI system processes input and produces output.
LLM fundamentalsSticky routing
Sticky routing is a model-routing or gateway concept used to manage traffic selection for AI requests. It describes a distinct decision, control, interface, or observation point between an application and one or more model providers.
Model routing and gatewaysStory points
Story points is a way to organize, support, or evaluate software work so that teams can make useful progress with less avoidable friction. It is most valuable when connected to a concrete outcome and the local conditions of the team using it.
Developer productivityStrangler fig pattern
Strangler fig pattern is a software maintenance concern describing a condition that can make future changes, verification, operation, or ownership harder. Its practical importance depends on supported behavior, rate of change, and the consequences of delay.
Code quality and technical debtStratified sampling
Stratified sampling is a defined lens for examining AI system behavior with a stated task, evidence, and interpretation rule.
Evaluations and benchmarksStream-aligned team
Stream-aligned team is a way to organize, support, or evaluate software work so that teams can make useful progress with less avoidable friction. It is most valuable when connected to a concrete outcome and the local conditions of the team using it.
Developer productivityStreaming inference
Streaming inference is the serving concept concerned with streaming inference during AI inference.
Inference performanceStreaming normalization
Streaming normalization is a model-routing or gateway concept used to manage interface consistency for AI requests. It describes a distinct decision, control, interface, or observation point between an application and one or more model providers.
Model routing and gatewaysStress testing
Stress testing is a software testing or test-design practice used to gather evidence about a defined risk, behavior, boundary, or operating condition. It makes the question under test explicit, identifies the inputs and observations that matter, and gives a team a repeatable basis for deciding whether the result is acceptable.
Code quality and technical debtStructured logging
Structured logging is writing log records as named fields instead of only free-form text.
Reliability and observabilityStructured output
Structured output is a model response constrained to a defined shape such as JSON with named fields and types. It gives application code a predictable contract while leaving the model responsible for generating the field values.
LLM fundamentalsStructured output normalization
Structured output normalization is a model-routing or gateway concept used to manage interface consistency for AI requests. It describes a distinct decision, control, interface, or observation point between an application and one or more model providers.
Model routing and gatewaysSubstantive review comment
A substantive review comment identifies a behavior, risk, question, or improvement that could change the author's decision or understanding.
Code reviewSubsystem testing
Subsystem testing is a software testing or test-design practice used to gather evidence about a defined risk, behavior, boundary, or operating condition. It makes the question under test explicit, identifies the inputs and observations that matter, and gives a team a repeatable basis for deciding whether the result is acceptable.
Code quality and technical debtSummary metric
Summary metric is a client-side statistical summary of observations, commonly count, sum, and selected quantiles.
Reliability and observability