A field test of Motto's risk estimator for suicide

The authors undertook a field test of Motto and colleagues' Risk Estimator for Suicide by selecting a subset (N = 593) of psychiatric patients with major or chronic affective disorder that corresponded to Motto's sample. They rated each subject on Motto's scale, using standardized data collected at hospital admission. Fourteen patients (2.4%) in their sample and 136 (4.9%) in Motto's sample died by suicide within 2 years. The authors tested the null hypothesis of a uniform suicide risk across all 10 deciles of risk scores by comparing observed and expected frequencies of suicide using the variance test for homogeneity of the binomial distribution. Their findings raise questions about Motto's risk scale but do not definitively invalidate it.