Symbols to Know

The level of evidence and strength of recommendation for each treatment according to North American guidelines have been rated with stars.

Level of evidence

1 out of 3 stars = Level III (lowest level of evidence)

2 out of 3 stars = Level II (moderate level of evidence)

3 out of 3 stars = Level I (strongest level of evidence)

Strength of recommendation

1 out of 3 stars = “C” rating (lowest strength of recommendation)

2 out of 3 stars = “B” rating (moderate strength of recommendation)

3 out of 3 stars = “A” rating (highest strength of recommendation)