​The IMLEC Performance Rating (IPR) is a historical ranking system designed to compare competitors across the entire history of IMLEC, from 1969 to the present day.

It is not simply a count of wins or an average finishing position. Instead, the rating looks at how well a competitor performed against the other drivers taking part in each individual competition, while also recognising finishing position, recent form and significant achievements.

Every competitor begins with an IPR of 1000.0. Their rating then rises or falls after each IMLEC they enter.

The basic principle

A strong performance increases a competitor’s IPR, while a weaker performance can reduce it. The size of that change depends partly on the strength of the opposition.

For example, beating a field containing several highly rated competitors is considered more significant than achieving the same finishing position against a lower-rated field.

This allows performances from different eras and different-sized IMLEC fields to be compared on a common scale.

The four parts of the calculation

For each classified IMLEC performance, the rating change is made up of four components.

1. Head-to-head performance — 65%

The largest part of the IPR calculation is based on head-to-head results.

Every classified competitor is effectively compared with every other classified competitor in that year's event.

For each comparison:

• finishing ahead of another competitor counts as a win;

• finishing behind counts as a loss;

• an equal finishing position counts as a draw.

The system then compares those actual results with what would have been expected from the competitors' IPR ratings before the event.

A lower-rated competitor who beats several highly rated competitors therefore gains more rating than a favourite who simply performs as expected.

Likewise, a highly rated competitor who finishes behind competitors they would normally be expected to beat can lose rating.

This head-to-head element makes up 65% of the normal performance calculation.

2. Finishing position — 15%

A further 15% is based directly on where the competitor finished within the classified field.

Rather than treating an 8th place identically every year, the calculation considers the size of the field.

For example, finishing 8th from 30 classified competitors represents a much stronger relative performance than finishing 8th from 10.

The top of the field receives a positive contribution, performances around the middle are broadly neutral, and lower finishing positions can produce a negative contribution.

3. Achievement bonuses — 15%

Major achievements receive additional rating bonuses.

The current IPR system awards:

• 1st place: +15 IPR

• 2nd place: +7 IPR

• 3rd place: +4 IPR

• Best 3½-inch performance: +10 IPR

These bonuses recognise achievements that are historically significant in their own right.

A competitor can receive both a finishing-position bonus and the Best 3½-inch bonus in the same competition.

4. Recent form — 5%

The remaining 5% considers a competitor's recent performances.

The system compares the current result with the competitor's recent relative finishing positions.

This provides a small reward when a competitor performs better than their recent form would suggest, or a small reduction when they perform below it.

The effect is deliberately modest. IPR remains primarily a measure of overall competitive performance rather than short-term form.

Rating scale

All competitors begin at:

1000.0 IPR

There is no fixed maximum or minimum rating.

A competitor consistently producing strong performances will gradually move above 1000, while weaker results can take a competitor below 1000.

Because the rating develops throughout a competitor's career, sustained success and repeated strong performances are rewarded.

Retirements, withdrawals and disqualifications

Different non-classified results are treated differently.

A retirement or disqualification receives a small rating reduction of 2 IPR points.

A withdrawal does not count as a performance and is excluded from the rating calculation.

A result recorded as Void is also excluded.

This means a competitor who entered IMLEC but never recorded a qualifying performance may appear in the Archive without having an IPR and will be shown as Not Rated.

Why can a rating change even without winning?

Winning is obviously highly valuable, but IPR measures more than victories.

A competitor can gain rating by:

• finishing significantly higher than expected;

• beating several highly rated competitors;

• producing a strong result in a large field;

• achieving a podium finish;

• winning the Best 3½-inch award;

• outperforming their recent form.

Likewise, a competitor can lose rating despite finishing reasonably well if the result was substantially below what their existing rating suggested they should achieve.

Why do some competitors who did not enter this year move up or down the ranking?

A competitor's IPR rating itself does not change if they do not compete.

However, their ranking position can change because other competitors may move above or below them after the latest IMLEC.

For example, a competitor may remain on exactly 1025.0 IPR but move from 40th to 41st because another driver has increased their rating sufficiently to pass them.

The movement arrows shown in the rankings therefore refer to ranking position, not necessarily to a change in the competitor's own IPR.

Ranking movement

The current ranking compares the latest IPR table with the previous year's table.

• ▲ indicates that the competitor has moved up the ranking.

• ▼ indicates that the competitor has moved down.

• — indicates no change in ranking position.

• NEW indicates a competitor appearing in the IPR ranking for the first time.

What is the purpose of IPR?

IPR is not intended to replace the official IMLEC results.

The competition result from each year remains exactly that: the result of that particular IMLEC.

Instead, IPR provides an additional way of exploring the Archive by asking a different question:

Across an entire IMLEC career, how strongly has this competitor performed relative to the opposition they faced?

By combining head-to-head performance, finishing position, achievements and form, the IPR provides a single evolving rating that can be used to compare competitors from across more than five decades of IMLEC history.