Investigating the MACH-IV with item response theory and proposing the trimmed MACH*.

The MACH-IV was investigated (N = 528) with item response theory to elucidate its psychometric properties and suggest a trimmed version, the MACH*. The core content of the MACH-IV seemed to be cynicism/misanthropy and the MACH* was formed from the 5 most informative and precise MACH-IV items. The MACH* showed good internal consistency and construct and criterion validity comparable to the MACH-IV. The MACH-IV and MACH* measure most precisely at average to above average levels of Machiavellianism. Implications for theory and measurement of Machiavellianism are discussed.