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. Author manuscript; available in PMC: 2013 Jun 16.
Published in final edited form as: J Speech Lang Hear Res. 2012 Jan 9;55(3):754–763. doi: 10.1044/1092-4388(2011/10-0216)

Table 1.

Item Parameter Estimates and Standard Errors across PPVT Test Forms

Item Parameter Mean SD Minimum Maximum
Difficulty (b) Estimate
 PPVT-3a (204 items) −0.32 1.35 −2.97 3.65
 PPVT-Rm (175 items) −0.28 1.37 −3.09 3.03
 PPVT-3b (204 items) −0.38 1.34 −2.78 3.03
Difficulty (b) Standard Error
 PPVT-3a (204 items) 0.08 0.07 0.02 0.37
 PPVT-Rm (175 items) 0.09 0.08 0.02 0.46
 PPVT-3b (204 items) 0.13 0.09 0.02 0.46
Discrimination (a) Estimate
 PPVT-3a (204 items) 1.52 0.65 0.17 3.39
 PPVT-Rm (175 items) 1.67 0.64 0.45 3.58
 PPVT-3b (204 items) 1.53 0.60 0.39 3.54
Discrimination (a) Standard Error
 PPVT-3a (204 items) 0.18 0.10 0.04 0.59
 PPVT-Rm (175 items) 0.22 0.09 0.08 0.44
 PPVT-3b (204 items) 0.27 0.14 0.08 0.93