IBM® SPSS® Amos™ 28
The acceptance rate is the proportion of times the Metropolis sampling algorithm generates a sample of parameter values that differs from the previous sample. For example, an acceptance rate of .2 means that, in generating a sequence of parameter values, the algorithm generates new parameter values 20% of the time and repeats the previous parameter values 80% of the time.
One rule of thumb is that MCMC algorithm is most effective when the acceptance rate is between .2 and .5. If you see that the acceptance rate is outside this range, it may be worthwhile to try adjusting the tuning parameter. If the acceptance rate is less than .2, try making the tuning parameter smaller. If the acceptance rate is greater than .5, try making the tuning parameter larger.
