RECOMMENDED ITN CALCULATION FORMULA
Once players have been rated, they will begin playing competitions. It will then be necessary, on the basis of matches played, to re-evaluate and re-rate the players on a regular basis. When competitive match results are used to adjust the players ITN rating, a decision will need to be taken regarding the most appropriate calculation formula to be used.
Type of system: The recommended ITN Calculation Formula system is a head-to-head system.
Which matches count towards the ITN? It is recommended that only matches recognised by Good News Tennis Ministries count towards the ITN i.e. so called official matches. These matches
can take place in a tournament. Official matches should be played under the ITF Rules of Tennis. So, if players want to have an ITN that is re-evaluated according to their match results, they should participate in competitions using match formats within the ITF Rules of Tennis.
When does the ITN calculation system start? Players will get their first ITN on the basis of their most recent competitive history or by participating in an ITN On Court Assessment conducted by an authorised person. From then onwards their ITN rating will be decided by results in official competitions or in the case of recreational players ITN 10 to ITN 7 by completing additional ITN On Court Assessments.
Who deals with the results of these matches? It is recommended that Good News Tennis Ministries be responsible for dealing with the results from official competitions or ITN On Court Assessments.
How often should the ITN rating be calculated? The ITN rating will be calculated after each tournament.
Is there a minimum number of matches required to get an ITN rating? It is recommended that the minimum of matches within the period of evaluation should be 6, but fewer matches are possible.
What about defaults and walkovers? In an effort to avoid players giving walkovers on a regular basis, players winning by walkovers should not be given points for these wins. In addition, if a player gives more than 3 walkovers in a year they should be penalised.
What if a player does not compete? Players who do not compete at all for more than a year will need to be rerated.
HOW DOES THE CALCULATION FORMULA WORK ?
The ITN Calculation can be done manually or run on an excel spreadsheet on a computer. The result of the calculation shows the player’s new ITN rating.
- For a win against a player of his own rating, a player gets + 1 point
- For a win against a player of one rating band higher, a player gets + 2 points
- For a win against a player of two rating categories higher, a player gets + 3 points etc.
- For a loss against a player of his own rating, a player gets – 1 point
- For a loss against a player of one rating band lower, a player gets – 2 points
- For a loss against a player of two rating categories lower, a player gets – 3 points etc.
- For a win against a player one or more rating categories lower or a loss against a player one or more rating categories higher, no points are given because these wins or losses are expected.
- NEW ITN RATING = (ACTUAL ITN) – (TOTAL POINTS ÷ NUMBER OF MATCHES)
Example of a player with ITN 5:
| ITN of player | ITN of opponent | points for win | points for loss |
| 1 | 5 | 0 | |
| 2 | 4 | 0 | |
| 3 | 3 | 0 | |
| 4 | 2 | 0 | |
| 5 | 5 | 1 | -1 |
| 6 | 0 | -2 | |
| 7 | 0 | -3 | |
| 8 | 0 | -4 | |
| 9 | 0 | -5 | |
| 10 | 0 | -6 |
| Matches played | Points earned |
| 7 losses against ITN 5: | -7 |
| 3 losses against ITN 4: | 0 |
| 3 losses against ITN 6: | -6 |
| 2 wins against ITN 5: | 2 |
| Total points: | -11 |
| Total points/number of matches | -11/15=-0.73 |
| New ITN rating | ITN 5 – (-0.73)=+5.73 |
| New ITN rating | ITN 6 (ie player goes down one band) |
Example of a player with ITN 8:
| ITN of player | ITN of opponent | points for win | points for loss |
| 1 | 8 | 0 | |
| 2 | 7 | 0 | |
| 3 | 6 | 0 | |
| 4 | 5 | 0 | |
| 5 | 4 | 0 | |
| 6 | 3 | 0 | |
| 7 | 2 | 0 | |
| 8 | 8 | 1 | -1 |
| 9 | 0 | -2 | |
| 10 | 0 | -3 |
| Matches played | Points earned |
| 3 wins against ITN 8: | 3 |
| 5 wins against ITN 9: | 0 |
| 4 losses against ITN 6: | 0 |
| 3 losses against ITN 7: | 0 |
| 2 losses against ITN 8: | -2 |
| 1 loss against ITN 9: | -2 |
| Total points: | -1 |
| Total points/number of matches | -1/18=-0.05 |
| New ITN rating | ITN 8 – (-0.05)=+8.05 |
| New ITN rating | ITN 8 (ie player remains in same band) |
Example of a player with ITN 10:
| ITN of player | ITN of opponent | points for win | points for loss |
| 1 | 10 | 0 | |
| 2 | 9 | 0 | |
| 3 | 8 | 0 | |
| 4 | 7 | 0 | |
| 5 | 6 | 0 | |
| 6 | 5 | 0 | |
| 7 | 4 | 0 | |
| 8 | 3 | 0 | |
| 9 | 2 | 0 | |
| 10 | 10 | 1 | 1 |
| Matches played | Points earned |
| 7 wins against ITN 10: | 7 |
| 2 wins against ITN 9: | 4 |
| 4 losses against ITN 9: | 0 |
| 2 losses against ITN 10: | -2 |
| Total points: | 9 |
| Total points/number of matches | +9/185=+0.6 |
| New ITN rating | ITN 10 – (+0.6)=+9.4 |
| New ITN rating | ITN 9 (ie player goes up one rating band) |