Saturation Review Memo¶
Stop review memo — instantiates Theory-Responsive Case Sampling Design
Documents whether newly sampled cases have stopped changing the model, and convenes the decision to stop.
A Saturation Review Memo is a structured review, written at a candidate stopping point, that documents whether recent cases have stopped changing the model at a stated resolution — and convenes the explicit decision to stop, pause, or continue. Its defining move is turning "we feel done" into a criterion-checked, reviewed stop with reasons on record. It exists to distinguish genuine conceptual saturation from its impostors: analyst fatigue, an exhausted budget, or a run of similar cases that merely looks flat. Where the loop's selection mechanisms decide what to sample next, this one decides whether to sample at all.
Example¶
A researcher has been interviewing employees at a mid-size firm about why they leave. Around the twenty-second interview, a familiar feeling sets in: the last several conversations have surfaced no new reason for leaving, only fresh phrasings of reasons already mapped. Before declaring the study done, the researcher writes a saturation review memo.
The memo states the resolution precisely: no new departure category has appeared in the last five interviews, though new illustrations of existing categories still arrive. It then checks the corners deliberately — has every stratum been heard? Two thin ones surface: night-shift staff and employees with more than ten years' tenure, both under-sampled. The memo records that the flat run came mostly from day-shift, mid-tenure workers, and convenes a small stop review. The decision is not "stop now" but "run three more interviews targeted at the thinnest strata, then stop if they too add no category." Saturation is treated as a claim to be earned at a stated resolution, not a feeling to be indulged.
How it works¶
- State the resolution. Name what "nothing materially new" means here — no new category, property, relation, process step, or boundary condition.
- Check the recent window against it. Examine the last several cases specifically for new structure at that resolution, distinguishing new categories from new mere illustrations.
- Audit the corners. Confirm the flat run isn't an artifact of a homogeneous recent sample; identify under-sampled strata.
- Convene the decision. Record a reviewed stop / pause / continue with its reasons and reviewers.
Tuning parameters¶
- Saturation resolution — category-level versus property-level versus decision-confidence. Coarser resolution saturates sooner but risks stopping while distinctions remain; finer resolution is rigorous but can prolong the inquiry indefinitely.
- Flat-run window — how many consecutive non-changing cases count as evidence of saturation. A longer window is safer but costlier.
- Stratum-coverage requirement — whether saturation must hold across all strata or only overall. Requiring per-stratum flatness guards against saturation-by-narrowness.
- Review level — a solo memo versus a stakeholder panel signing off. More reviewers add legitimacy and friction.
When it helps, and when it misleads¶
Its strength is that it makes stopping a decision rather than a default, guarding simultaneously against endless sampling and premature closure. A stated saturation criterion, checked and reviewed, is what lets an inquiry end defensibly instead of drifting or quitting when the researcher tires.[1]
Its central failure mode is saturation-by-narrowness: declaring saturation from a recent run that only looks flat because the last few cases were too similar to each other, so the model appears settled while whole regions of the case universe remain unheard. The classic misuse is the ritual saturation claim — citing the concept in a methods section without ever checking the under-sampled corners. The guarding discipline is to require an explicit audit that negative, boundary, and thin-stratum cases were examined before a flat run is trusted as saturation.
How it implements the components¶
A Saturation Review Memo fills the stopping slice of the archetype, not its selection or preservation slices:
conceptual_saturation_criterion— it states and applies the stop rule at a named resolution, defining what "nothing materially new" means for this inquiry.sampling_stopping_review_panel— it convenes and records the stop / pause / continue decision and the reviewers who signed off.
It does not preserve the full versioned trail of the sampling path — that is Case Selection Audit Trail via memo_version_history; nor does it author the learning question for a next case, which is Grounded Theory Sampling Memo via case_learning_question.
Related¶
- Instantiates: Theory-Responsive Case Sampling Design — supplies the reviewed stop rule that ends the loop defensibly.
- Consumes: Constant Comparison Matrix — supplies the recent revision trend the memo judges for flatness.
- Sibling mechanisms: Boundary Case Probe · Case Selection Audit Trail · Constant Comparison Matrix · Grounded Theory Sampling Memo · Maximum Variation Case Round · Negative Case Sampling Pass · Rival Explanation Discriminator · Theoretical Gap Matrix · Transferability Claim Check
Editorial Notes¶
Form Classification¶
Form family: Assessment, Review & Assurance
Rationale: Saturation Review Memo operates as a bounded evaluation of existing evidence or work that produces a finding or disposition because it documents whether newly sampled cases have stopped changing the model, and convenes the decision to stop.
Independent corroboration: The frozen evidence defines Saturation Review Memo as 'Documents whether newly sampled cases have stopped changing the model, and convenes the decision to stop', so its operative form is Assessment, Review & Assurance.
Nearest alternative: Representation, Specification & Plan — Saturation Review Memo includes features of a static representation, map, specification, schema, or prospective plan that externalizes information, but its defining operation is a bounded evaluation of existing evidence or work that produces a finding or disposition.
Review outcome: Independent reviewer agreement; medium confidence.
Origin Attribution¶
Primary origin: Ethnography & Qualitative Methods
Origin pattern: Cross-disciplinary synthesis
Present-day reach: Multi-domain
Rationale: Stopping when additional cases cease changing a model is canonical qualitative saturation.
Related originating lineages:
- Organizational & Management Science — Decision memos materially formalize and govern the stop decision.
- Sociology & Anthropology — Sociology and anthropological study of institutions and social relations supplies a parallel or contributing lineage for the mechanism's defining operation: documents whether newly sampled cases have stopped changing the model, and convenes the decision to stop.
- Statistics & Experimental Design — Statistics, experimental design, and measurement theory supplies a parallel or contributing lineage for the mechanism's defining operation: documents whether newly sampled cases have stopped changing the model, and convenes the decision to stop.
Review resolution: Both blind reviewers agree that ethnography_qualitative_methods is the primary historical origin. Explicit reconciliation of alternate_origin_disagreement, origin_mode_disagreement, encyclopedia_synthesis_disagreement starts from reviewer_a's mechanism-specific evidence: Stopping when additional cases cease changing a model is canonical qualitative saturation. Reviewer A proposed alternates=organizational_management, origin_mode=convergent, domain_reach=multi_domain, and encyclopedia_synthesis=false; reviewer B proposed alternates=sociology_anthropology, statistics_experimental_design, origin_mode=cross_disciplinary_synthesis, domain_reach=multi_domain, and encyclopedia_synthesis=true. The final record retains every independently supported alternate from either review (organizational_management, sociology_anthropology, statistics_experimental_design) without an arbitrary cap, selects origin_mode=cross_disciplinary_synthesis to represent the combined lineage evidence, and records domain_reach=multi_domain and encyclopedia_synthesis=true. Present-day transfer is recorded as reach and is not treated as proof of historical origin.
Encyclopedia synthesis: The exact catalogued form synthesizes established practice rather than reproducing a single standard historical label.
Review outcome: Reconciled after independent review; medium confidence.
References¶
[1] Theoretical saturation — from Glaser and Strauss (1967), the point at which additional data no longer yields new properties, categories, or relations for the emerging theory. It is a claim about conceptual return at a stated resolution, not a statistical guarantee that no future case could ever matter. withdrawn registry ↩