To ensure that our road rankings are fair and that the performances included are reasonably comparable betweeen different races and courses on different days, we use the following guidelines to determine whether the times can be included in our rankings. These are similar to those adopted by World Athletics (Rule 260) and the ARRS - the Association of Road Racing Statisticians.

Road performances are classified as "record quality", "statistically valid", or "statistically invalid" based on the start/finish separation, the net drop of the course and the effect of weather conditions.

Record Quality - all of the following must apply
- Start/finish separation is less than 50% of the race distance and the net drop is less than 1.0 m/km
- The net effect of tailwind and/or drop as measured by our SSS metric does NOT indicate that a signficant advantage was gained
- Has a valid measurement certificate and no evidence that the course, as measured, was not run in full

Statistically Valid (suffix "a") - all of the following must apply if does not meet Record Quality status
- The net drop is less than 5.0 m/km
- The net effect of tailwind and/or drop as measured by our SSS metric does NOT indicate that a signficant advantage was gained
- Has a valid measurement certificate and no evidence that the course, as measured, was not run in full

Statistically Invalid - if any of the following apply
- The net drop is 5.0 m/km or more
- The net effect of tailwind and/or drop as measured by our SSS metric indicates that a signficant advantage was gained
- Does not have a valid measurement certificate
- Less than the advertised distance was run

Only record quality performances are eligible to be considered for UK records. Record quality and statistically valid performances are included in our rankings lists. However, due to the nature of our handicap scoring scheme and the SSS metric, all these races are included for athlete handicaps and so can contribute to the national ladder positions.

If a race is statistically invalid then we will alter the event codes as following:
NAD - near as dammit. This is when the length of a course is thought to be about right but there is no official measurement certificate.
DH - downhill. This is when the principle reason for any advantage is the net drop.
SHORT - short course.
MT - multi terrain - these are races that are not predominatly on the road and so, by definition, do not count for road rankings.
So, for example, instead of a regular 10K the variants would be 10KNAD, 10KDH, SHORT10K, 10KMT.

Generally any races that have a negative SSS value might be considered to have offered an unfair performance advantage and be subject to further investigation.

Note that for UK road races, a current official course measurement certificate as issued by the Association of UK Course Measurers (AUKCM) is a requirement of a runbritain/UKA road race licence. Their companion Course Measurement website provides full details of current UK certificates. For overseas races we will exclude any races that are not obviously measured to similar standards.