Uniform interpretation
The instructions apply to assistant referees in matches in all of UEFA's competitions, and have been compiled with the objective of reinforcing the uniform interpretation and application of the Laws of the Game.

UEFA Referees Development Programme 2000/01
1st Seminar for Assistant Referees
16-18 July 2001
UEFA Headquarters - House of European Football, Nyon

General Conclusions
Attention is drawn to the following decisions made at the 1st UEFA Seminar for international assistant referees for the benefit of international football in Europe by adopting a standard approach in the performances of assistant referees.
It was felt that these practices will reinforce the uniform interpretation and application of the Laws of the Game.

Offside
1. If an assistant referee has any doubt about an offside offence the flag should not be raised (ie. benefiting the attacking team).
2. To ensure correct judgement of offside offences, an assistant referee should not raise the flag before considering the following criteria, so called "wait and see" technique:
a. Movement of the ball (direction, speed, distance, any deflection, etc.)
b. Involvement of the player in active play by: 
• interfering with play or 
• interfering with an opponent or 
• gaining an advantage.
3. If a flag signal for offside is given and is not seen immediately by the referee; the assistant referee must keep signalling until it has been recognised or the ball is clearly in control of the defending team (the electronic beep signal is used to alert the referee to the flag signal).

Ball out of the field of play
4. Whenever the ball leaves the field of play, the flag signal of the assistant referee should show clearly the correct restart and direction. In clear throw-in situations, the assistant referee can directly show the direction (along the whole touch line). But if he has any doubt about the direction, the assistant referee should simply raise his flag, make eye contact with the referee and follow the referee's signal.
On very tight decisions, when the ball stays in play, a discreet hand signal could give valuable support to the referee.
5. Whenever an assistant referee signals the ball out of the field of play (even if players continue to play the ball) he must retain the signal until acknowledged by the referee taking action.
6. When the ball enters a goal:
To confirm a valid goal has been scored, an assistant referee should display clear movement down the touchline towards the centre line. In borderline cases, this movement should be clear (sprint) to be recognised by the referee. To confirm a goal, the assistant referee should not raise his flag.
If in his opinion a goal has not been scored correctly, the assistant referee should stand still, retaining any signal already given. The referee may then choose to consult further if he needs additional guidance.

Offences
7. An assistant referee must use a raised flag signal to advise the referee that he has seen a foul committed (or unsporting behaviour or violent conduct) when he is better positioned than the referee and the referee has not clearly acted on the offence. If the assistant referee has additional information, concerning the offence, he wishes to give to the referee or if the referee has not seen his flag signal the electronic beep signal should be used.
It was agreed that such action by an assistant referee will be taken for all appropriate offences including those committed inside the penalty area.
8. If a flag signal for any offence is not seen immediately by the referee, the assistant referee must keep signalling until he is acknowledged by the referee or he recognises a clear advantage to the team against which the offence has been committed.
9. Offences of violent conduct seen and signalled by an assistant referee must be acted upon in accordance with the Laws of the Game by the referee. If play has been stopped for the disciplinary action (even if the signal has not been seen immediately and play has continued), the restart must also be in accordance with the Laws (free kick / penalty kick). However, if the assistant referee's signal is not seen immediately and play has been restarted for a subsequent situation only the appropriate disciplinary action can be taken against the offending player.
10. Where a referee seeks guidance from an assistant referee concerning the exact location of an offence near the boundary of the penalty area the action of the assistant referee should be as follows:
a. If the offence is inside the penalty area - the assistant referee moves visibly down the touchline towards the corner flag.
b. If the offence is outside the penalty area - the assistant referee stands still having moved to be in line with the edge of the penalty area.

Obvious incorrect decision of the referee
11. If an assistant referee knows that a referee has made an obvious disciplinary error (eg. two yellow cards to the same player without sending him off, red or yellow card to the wrong player, player kicked the ball twice at free kick, etc) he must intervene immediately (flag and beep or even enter the field of play). The other assistant referee (or 4th official) should if necessary, also assist in such case.

Control of the 9.15m distance
12. When a referee chooses to use the help of an assistant referee on the field of play to control the 9.15m distance from the ball at free-kick, it is recommended that the assistant referee does not physically measure the 9.15m but rather asserts his control from the position of the ball. This exceptional on field involvement of the assistant referee is recommended only for free kicks very near the touchline.

Positioning
Free kick close to the penalty area
13. At free kicks close to the penalty area, the assistant referee should position himself in line with the second last defender (controlling the offside), but also with awareness of the goal line. The referee should control the ball and the wall.

After an offside
14. When possible an assistant referee, after a free kick for offside has been given, should position himself in line with the spot where the ball should be positioned to restart the game. He should then immediately take up a position to control the offside line (level with the second-last defender), which is his priority.

Goal kick and goal clearance
15. For goal kicks and when the goalkeeper is in possession of the ball inside his own penalty area, it is advised that the assistant occasionally checks that the ball is correctly positioned or that the goalkeeper does not cross the 16 metre line before releasing the ball from his hands. This should be done in convenient situations (eg. second last defender near the penalty area). Control of offside from subsequent play is the priority concern.

Corner kick
16. For corner kicks, it is recommended that the assistant involved takes a position behind the flag in line with the goal line.

Penalty kick
17. When a penalty kick is awarded during the normal course of play, the assistant should be on the goal line where it meets the penalty area boundary line.
18. For kicks from the penalty mark to determine the winner of a match, one assistant should be positioned on the goal line where it meets the goal area boundary line, with the other assistant controlling the players within the centre circle.

Substitution
19. When a substitution takes place, the assistant referee 1 should move towards the halfway line and assist the 4th official in the procedure. When the procedure is fully completed, the assistant referee will take his position and then give a signal for the restart to the referee. Special awareness should be given in case of simultaneous substitutions and / or a substitution immediately after a red card.

Flag technique
20. It is recommended that an assistant referee holds the flag in his hand nearest to the field of play by switching hands whenever he changes his direction of movement so that the flag is visible to the referee at any time. It is suggested to the associations to instruct new assistant referees in this way, however this technique is not compulsory for experienced assistant referees. The referee observer shall continue to assess the performance of the assistant referee according the accuracy of his decisions.