The shape of it
Strip away the notation and every one of these systems does the same three things. It decides how much the day is worth, it splits that between distance and speed, and it decides who gets which. The disagreements are about the third question, and they are larger than most pilots realise.
Everything below is from the current primary documents: FAI Sporting Code Section 3 Annex A, 2025a edition, and the 2026 SSA Official Competition Rules. You can put a day through all four systems on the scoring calculator and watch the differences appear.
Why the winner never scores 1000
A day starts with a ceiling. Under IGC rules the maximum available score is the least of three things: 1000, a term that falls away if the best handicapped distance is under the class's reference distance, and a term that falls away if the winner took less than three hours. Short task or quick day, and the ceiling drops before anyone is scored.
Then two factors are applied to everybody, and this is the part that gets forgotten:
- The Day Factor asks what fraction of the launched field reached the day's minimum distance. Below 80%, everyone loses points. Not the ones who landed out — everyone, including the winner.
- The Completion Ratio Factor asks what fraction of those got home fast. It floors at 0.6, so a day where nobody finishes is still worth 60% of what it would otherwise have been.
So on a day with a full ceiling of 1000 points, a winner might take 825 — not because they flew badly, but because a third of the field landed out. Your score depends on other people's flying. That is deliberate: it is how the rules distinguish a hard day from an easy one without anyone having to judge it.
The two-thirds cliff
Here is the sharpest edge in the IGC Classic system, and the one worth flying to.
Speed points are awarded on a line that starts at two thirds of the winner's handicapped speed and runs up to the winner. Below that threshold you get none. Not fewer — none. It is a cliff, and it sits in a place slow finishers land on more often than they expect.
What softens it is the other half of the score. Under IGC Classic, every finisher receives identical distance points, regardless of how far they actually flew. On a racing task everyone who gets home has flown the same task distance, so the distance component simply cannot separate them; it separates finishers from landouts, and nothing else.
Put those together and the incentive is stark. Getting home is worth an enormous amount, and the last few percent of speed is worth relatively little. A pilot who finishes at half the winner's speed scores nothing on speed and still comfortably beats someone who landed out twenty kilometres short.
Where the handicap goes, and the trap
A handicap does exactly two things under IGC rules: it divides your distance, and it divides your speed. That is all. It never touches points, and it never touches time.
A higher IGC handicap means a better glider, so dividing by it takes more away. Club Class runs from 0.988 to 1.080, and the list and its adjustment rules are published — though note the IGC republishes that document whenever it likes and the URL pattern changes with it, so an old edition is easy to mistake for the current one. The 2026 revision widened the band and moved individual types by more than a point.
The US SSA convention is the exact reciprocal. A lower SSA number means a better glider, and the formula multiplies rather than divides. The two relate as Hssa = 1 / Higc. Both scales sit within a few percent of 1.0, so mixing them up does not produce anything that looks obviously wrong — it produces a results sheet in quietly the wrong order.
There is a second-order effect worth knowing. Because a finisher's distance points are flat, the handicap affects a finisher's score only through speed. For a landout it works the other way: the handicap only touches their distance ratio. The same number does different work depending on whether you got home.
Five systems, three reference gliders
It is worse than two conventions. There are at least five handicap systems in active use, and they do not agree about what the middle of the scale is:
- IGC and the German DAeC/DMSt index both normalise on the ASW 19 — 1.000 and 100 respectively.
- The BGA Speed Index normalises on the LS 8 at 100, and runs from 46 to 119.5.
- The SSA normalises on the Standard Cirrus at 1.000, and is the one that counts backwards.
- The OLC uses a fork of the German list that lags it by a point or two on modern gliders, on a page carrying no version date at all.
Two of these can be compared directly, because the SSA scale is the reciprocal of the IGC one. Do that across the types both lists cover and they agree exactly on one aircraft — the Standard Cirrus, at 1.000 on both — then diverge by 1.6% on average and up to 3.4%. Set against an IGC Club Class band only 9.3% wide, the disagreement between two national authorities is a substantial fraction of the entire performance spread they are trying to measure. The comparison table has the numbers.
None of them is wrong. They were derived from different weather models for different fleets: the German list explicitly represents a whole soaring day, and the DAeC now publishes a second, compressed list for on-site competitions on the grounds that a contest is flown in the best hours and that slower gliders gain disproportionately from following a gaggle. The BGA normalises at an average climb of 2.5 knots. Three separate national bodies have independently concluded that a general-purpose index over-compensates slow gliders in a mass-start race, and all three have narrowed their spread in response. That convergence is the strongest thing that can be said for the state of the art.
There is one asymmetry worth naming. The IGC's list is traceable to a published DLR paper. The BGA publishes its committee's reasoning, though not the underlying flight-test reports. The SSA publishes its weight-adjustment derivation in full and does not publish how the base handicaps themselves are produced — no polar source, no algorithm, no stated reference conditions. Pilots have been asking since at least 2011, and it is still the case.
The American formula is a different animal
US contests run two systems in one rulebook. The FAI classes use what is essentially the IGC Alternative Scoring system. Regional contests and Sports Class Nationals use something with no IGC counterpart at all, and the design philosophy is close to opposite.
- A finisher has a guaranteed floor. However slowly you get home, you cannot score below a defined minimum. IGC Classic has no such floor.
- The low-speed region is deliberately flattened. Every speed from zero to 40% of the winner's scores the same, and the next stretch earns only about two points per one percent of speed. IGC pays zero below two thirds; the US pays a constant below two fifths. Same problem, opposite answers.
- Distance points rise as fewer people finish. The share of the day allocated to distance grows from 60% to 80% as the completion ratio falls. On a hard day the rules quietly rebalance toward rewarding distance flown.
The published rationale is explicit about the intent: compressing the low-speed region means "going one mile per hour faster is only important if you're already pretty fast", so slower or unluckier pilots should behave more cautiously. Whether that works is arguable. That it is a deliberate design choice, rather than an accident of arithmetic, is not.
Assigned areas, and the thing that is not a penalty
On an assigned area task there is a minimum time, and a great many pilots believe finishing early carries a penalty. It does not. Annex A contains no under-time penalty of any kind.
What happens instead is purely arithmetic: for a finisher, marking time is the greater of the elapsed time and the minimum task time. Come home twenty minutes early and the rules score you as though you took the full time, so your computed speed drops. Your distance is untouched — you keep every kilometre you flew.
Which is why the strategy on an assigned area task is to fly further, not faster, once you are inside minimum time. There is no clock to beat; there is only a denominator you cannot make smaller.
US Turn Area and Modified Assigned tasks differ here, and it is a real difference. They use a hybrid rule that gives back a tenth of the under-time, which makes finishing promptly optimal once your last turn is achieved. Same-looking task, opposite advice.
Three things that will surprise you about the numbers
A disqualified pilot still counts. Their score is zero, but they remain in the field for the day factors. A disqualification therefore lowers everyone else's score slightly, which is not what most people assume.
The reference distance and the reference speed usually belong to different pilots. The day's greatest handicapped distance sets one term; the fastest finisher sets another. Neither fact alone decides the winner, and a pilot can set the distance reference and still place third.
The formula changed, and the old one is easier to find. Until fairly recently, handicapped distance was normalised to the lowest handicap in the field. That term no longer exists — it is now simply distance divided by handicap. A completion-ratio factor was added that did not previously exist, and the reference distance for a full-value day now varies by class. If you are reading a formula somewhere and it contains a term normalising to the lowest handicap, you are reading a superseded edition.
Where even the officials disagree
This is the part that is genuinely startling, and it is documented by the IGC itself rather than by critics.
Scoring a day from a set of flight logs requires measuring distance, and measuring distance requires a model of the Earth. Annex A used to specify one — a sphere of a stated radius. That specification was removed and not replaced. The current rules say distances are measured along geodesics without saying geodesics on what. Two conforming implementations can therefore disagree.
This is not new. A report to the IGC plenum from its own scoring software group states plainly that programs use a combination of Earth models — an ellipsoid for distances, a sphere for deciding whether a line was crossed — that no computational standard exists, and that the IGC does not know whether the different programs blend the algorithms the same way.
The assigned area case is worse still: the rules say only that the scorer chooses the set of fixes producing the maximum distance, and specify no algorithm, no tolerance and no convergence criterion for a genuinely difficult optimisation.
And in one documented case the reference implementation is knowingly wrong: the Alternative Scoring system's compression step requires the median score — the rule says so in bold — while the widely used open-source scoring script computes the mean, and says so in a code comment.
None of this is a scandal. It is what happens when a rulebook written in prose meets a numerical problem, and the people involved are volunteers who have documented their own uncertainty honestly. But it does mean that a score is the output of a specific program, not of a formula, and that two entirely legitimate scorers can produce different numbers from the same traces.
What to do with all this
- Get home. The single largest step in every one of these systems is the one between finishing and not finishing. Everything else is smaller.
- Know which side of the cliff you are on. Under IGC rules, if you are going to finish below two thirds of the leader's speed anyway, further pushing buys you nothing at all — and it is exactly the situation where pushing is tempting.
- On an assigned area task, extend rather than hurry — unless you are flying US regional rules, where the opposite is true.
- Check which handicap scale a number is on before you use it. They are reciprocals and both live near 1.0.
- Read your own contest's local procedures. Several things that matter — the low-finish penalty constant, the observation zone geometry on a handicapped distance task — are deliberately not in the international rules at all. They are set locally, and they differ.