Both MMSE and MoCA are two widely used cognitive screening test. Comparison of the two tests has been done in specific populations (Parkinson) but not in general elderly psychiatric populations. In research, equating methodologies has been used to compare results among studies that use different scales, which measure the same construct.

To explore their level of agreement within a particular clinical setting.

(a) To find MoCA and MMSE agreement. (b) To derive a conversion formula between the two scales and test it in a random population of similar setting.

Prospective study of consecutive community dwelling older patients who attend outpatient clinic or day hospital. Both tests were administered from the same researcher the same day in random order.

The total sample (n = 135) was randomly divided in two. One from where the equating rule derived (n = 70) and a second (n = 65) in which the derived conversion was tested. Agreement of the two scales (Pearson's r) was 0.86 (P < 0.001), and Lin's Concordance Correlation Coefficient (CCC) was 0.57 (95% CI 0.45–0.66). In the second sample, we convert the MoCA scores to MMSE scores according to equating rule from the first sample and after we examined the agreement between the converted MMSE scores and the originals. The Pearson's r was 0.89 (n = 65, P < 0.001) and the CCC 0.88 (95% CI 0.82–0.92).

Although the two scales overlap considerably, the agreement is modest. The conversion rule derived showed promising accuracy in this population but need further testing in other populations.

The authors have not supplied their declaration of competing interest.