Expert consensus of the Chinese Association for the Study of Pain on pain treatment with the transdermal patch

Table 6 Quality classification and definition of grade evidence

Quality level	Definition
High (a)	Very sure that the true effect value is close to the effect value estimation
Medium (b)	There is a moderate degree of confidence in the value of effect; the real effect value may be close to the estimated value, but there is still a possibility that the two are not the same
Low (c)	There is limited confidence in the effect estimates; the true effect values may not be the same as the effect estimates
Very low (d)	There is little confidence in the estimated effect; the true effect value may be quite different from the effect estimate