Administrative vs. Classical vs. Performance Swim Conversions — What’s the Difference?

[SwimGPT]

🏊 Swim Standards Conversion Modes Explained

(Classical vs Administrative vs Performance)

Swim Standards supports multiple conversion models between Short Course Yards (SCY), Short Course Meters (SCM), and Long Course Meters (LCM).

These models are not equally “accurate”—they are different tradeoffs between coverage, consistency, and purpose.
As a reminder: any conversion is an estimate, and real-world outcomes depend on the swimmer, pacing, and turns.

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✅ Classical (Colorado Additive–Scaling Model) — Default

Classical is the default on Swim Standards because it offers the most complete and consistent coverage across events and courses.

It uses a combination of:

• fixed scaling factors (yards ↔ meters)
• fixed additive adjustments (turn/wall effects)

This method is widely used in the swimming community and tends to produce results that are stable and “close enough” for most comparisons.

Coverage

• Supports SCY ↔ SCM ↔ LCM
• Supports the full set of events Swim Standards tracks (including distance freestyle mappings)

Recommended when

• You want a consistent, full-coverage conversion across courses
• You want a practical approximation for comparisons, rankings, and browsing

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🏫 Administrative (NCAA) — Published Factors

Administrative (NCAA) follows published NCAA conversion factors used for qualification and seeding.
This model is designed for administrative consistency, not performance prediction.

Coverage

• Supports SCM → SCY (published short-course meter factors)
• Supports LCM → SCY (published long-course meter factors)
• Does not support direct SCM ↔ LCM
• Does not support 50 Backstroke, 50 Butterfly, 50 Breaststroke (no conversion factors are published in the 2025–26 NCAA Division I standards; the most recent were from 2023-24)

Recommended when

• You are checking NCAA-related equivalency, qualification, or seeding-style conversions
• You want the conversion to follow published NCAA factors exactly

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⚙️ Performance (Regression-Based) — Experimental

Performance is an experimental model based on regression-style coefficients (a, b) tuned using historical swim performance data.

It uses a linear form:

LCM Time = a + b × SCY Time
(time in seconds)

This model is intended for performance-style estimation, but because it relies on fitted coefficients, it may change as data and tuning evolve.

Coverage

• Supports SCY → LCM only
• Does not provide full SCM support
• Not all factors are equally mature; some are estimated and may be revised

Recommended when

• You want to explore performance-style estimates for SCY→LCM
• You understand results may differ from published administrative conversions

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✅ Summary Comparison

Model	Purpose	Coverage	Recommended Use
Classical (Default)	Practical, consistent estimates	SCY ↔ SCM ↔ LCM (full coverage)	Most day-to-day comparisons
Administrative (NCAA)	Published NCAA equivalency	SCM→SCY, LCM→SCY only	NCAA qualification/seeding checks
Performance (Experimental)	Regression-style estimate	SCY→LCM only	Exploratory analysis

📊 Conversion Accuracy Comparison (Using 2026 Futures Standards)

The following table compares converted LCM times against the official 2026 USA Swimming Futures standards, which publish both SCY and LCM times for the same performance level.

• SCY is used as the source time
• LCM (Expected) is the published Futures standard
• Differences show (Converted − Expected)
• Negative values indicate a faster-than-expected conversion

This provides a real-world benchmark for evaluating conversion accuracy.

Event	Sex	SCY	Expected LCM	Classical	Δ	Performance	Δ	NCAA	Δ
50 FR	F	23.89	27.39	27.32	−0.07s	27.14	−0.25s	27.11	−0.28s
50 FR	M	21.29	24.59	24.43	−0.16s	24.03	−0.56s	24.47	−0.12s
100 FR	F	51.89	59.29	59.20	−0.09s	58.40	−0.89s	58.69	−0.60s
100 FR	M	46.39	53.59	53.09	−0.50s	51.95	−1.64s	53.13	−0.46s
200 FR	F	1:52.29	2:07.79	2:07.84	+0.05s	2:04.69	−3.10s	2:07.02	−0.77s
200 FR	M	1:41.59	1:57.79	1:55.96	−1.83s	1:52.44	−5.35s	1:56.10	−1.69s
400 / 500 FR	F	5:02.59	4:28.79	4:30.06	+1.27s	4:32.61	+3.82s	4:29.68	+0.89s
400 / 500 FR	M	4:37.09	4:09.99	4:07.30	−2.69s	4:09.66	−0.33s	4:08.51	−1.48s
800 / 1000 FR	F	10:20.49	9:13.79	9:13.79	+0.00s	9:18.98	+5.19s	9:09.10	−4.69s
800 / 1000 FR	M	9:34.29	8:40.69	8:32.55	−8.14s	8:37.27	−3.42s	8:35.05	−5.64s
1500 / 1650 FR	F	17:14.39	17:40.19	17:35.08	−5.11s	17:43.58	+3.39s	17:30.14	−10.05s
1500 / 1650 FR	M	16:05.49	16:38.99	16:24.80	−14.19s	16:32.80	−6.19s	16:30.24	−8.75s
100 BK	F	57.09	1:06.79	1:04.57	−2.22s	1:04.32	−2.47s	1:06.15	−0.64s
100 BK	M	51.49	1:00.59	58.35	−2.24s	57.70	−2.89s	1:00.93	+0.34s
200 IM	F	2:06.39	2:26.19	2:23.49	−2.70s	2:20.73	−5.46s	2:24.11	−2.08s
200 IM	M	1:53.89	2:12.79	2:09.62	−3.17s	2:06.21	−6.58s	2:11.36	−1.43s
400 IM	F	4:30.69	5:07.29	5:06.87	−0.42s	4:54.19	−13.10s	5:05.51	−1.78s
400 IM	M	4:06.99	4:42.39	4:40.56	−1.83s	4:27.33	−15.06s	4:42.27	−0.12s

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📌 Conclusion

Using the 2026 USA Swimming Futures standards as a benchmark (paired SCY and LCM times), several clear patterns emerge:

1️⃣ Classical is the most stable and consistent

• Errors are generally small and predictable across all strokes and distances.
• Provides complete event coverage, including 50s and long-distance freestyle.
• Performs well across sprint, middle-distance, and distance events.

2️⃣ Performance mode shows larger variance

• Tends to undershoot LCM times, especially in IMs and longer events.
• Error magnitude increases with distance.
• Best viewed as experimental and analytical, not authoritative.

3️⃣ NCAA is accurate where supported — but incomplete

• Often very close to Futures standards when applicable.
• Does not support:
  • 50 Back, 50 Fly, 50 Breast
  • SCM ↔ LCM conversions
• Intended strictly for administrative qualification, not performance analysis.

✅ Practical Takeaway

For Swim Standards:

• Classical is the most reliable default due to its coverage, consistency, and stability
• NCAA is best used for eligibility and seeding checks
• Performance should be treated as experimental, useful for comparison but not definitive

This is why Swim Standards now defaults to the Classical conversion model, while still allowing users to compare results across all three approaches.