Research question
What should a small operation measure to distinguish reliable supplier delivery from a reassuring aggregate percentage?
Evidence
The Supply Chain Operations Reference model developed by the Association for Supply Chain Management organizes supply-chain performance attributes and measures, including reliability and responsiveness. NIST’s statistical handbook shows why variation and distribution shape matter alongside averages.
Those frameworks imply that delivery performance needs a defined event pair and more than one summary statistic. They do not establish a universal supplier threshold.
Operations-specific analysis
An “on-time” rate is reproducible only if the team defines the committed date, delivery event, allowed tolerance, partial shipments, customer-requested changes, and supplier-approved changes. Replacing the original promise with a later revised date can make performance look better while hiding instability. Both dates should be retained.
For each order line or shipment, record original commit, current commit, actual receipt, completeness, exception reason, and evidence source. Report on-time-in-full against the original commitment, median lead time, a high lead-time percentile, and the frequency and timing of promise changes. Segment by item criticality or supplier rather than averaging unlike flows.
The result still needs context. A late shipment caused by an approved buyer change is operationally different from an unexplained miss. Reason codes should describe verified events and remain separate from decisions about accountability. A coordinator may reconcile acknowledgments, track milestones, and prepare exceptions. Procurement owners select suppliers, accept revised terms, approve substitutions, and resolve commercial disputes.
Conclusion
Aggregate on-time delivery can conceal incomplete orders and repeated promise revisions. A stable event model that preserves original commitments and shows variability gives leaders a stronger basis for contingency planning. The immediate research task is data validation, not ranking suppliers from inconsistent records.
Sources and limits
- ASCM SCOR Digital Standard, a supply-chain process and performance reference.
- NIST/SEMATECH e-Handbook of Statistical Methods, methods for describing variation and distributions.
SCOR is a reference model, not a causal study or contractual definition. Local purchase terms and operational consequences determine the appropriate measures.