Objective: An, Zakzanis and Joordens (2012) examined the neuropsychological test performance of undergraduates and reported 55.6% of their sample performed below performance validity test (PVT) cutoffs. However, recent studies report much lower rates of suboptimal performance (Santos et al., 2014; Silk-Eglit et al., 2014). Given the dearth of studies in this area, we examined performance invalidity base rates in a sample of college students. Method: Healthy undergraduates (N = 108; M Age = 19.83; 76% female; 72% Caucasian) enrolled in psychology courses at a southeastern university were administered the Victoria Symptom Validity, Dot Counting, and Word Memory Tests. Four additional measures were given upon initial assessment or when reexamined at time 2 (M interval = 34.4 days). Results: At initial testing, 6.48% of the sample (n = 7) scored below cutoffs on at least one PVT and most indices yielded lower percentages (see Table 1). Three participants (2.8%) scored below cutoffs on at least one PVT at time 2 and most performed within normal ranges on additional tests (see Tables 2 &3). Conclusion: The present findings add to a body of evidence supporting low base rates of suboptimal effort in college students. The disparity between recent findings and those of An et al. are likely attributable to differences across samples & cutoffs used. At present, only three published studies directly examine suboptimal effort on neuropsychological testing in undergraduates, so more research is clearly needed.

Table 1.

Means, SDs and percent of sample below cutoffsa on performance validity tests at Time 1 and Time 2 (n = I08)b

Test Mean Time 1 (SD) % Below Mean Time 2 (SD) % below 
DCT-E 9.55 2.31 4.6% 8.54 2.15 2.8% 
VSVT -D 23.56 .89 0% 23.28 1.1 0.9% 
WMT-IR 97.38 5.52 2.0% 99.19 1.95 0% 
WMT-DR 97.73 5.34 0.9% 98.37 1.53 0% 
WMT-C 97.75 5.02 2.0% 98.70 2.78 0% 
Test Mean Time 1 (SD) % Below Mean Time 2 (SD) % below 
DCT-E 9.55 2.31 4.6% 8.54 2.15 2.8% 
VSVT -D 23.56 .89 0% 23.28 1.1 0.9% 
WMT-IR 97.38 5.52 2.0% 99.19 1.95 0% 
WMT-DR 97.73 5.34 0.9% 98.37 1.53 0% 
WMT-C 97.75 5.02 2.0% 98.70 2.78 0% 

Note. DCT-E = Dot Counting Test E Score; VSVT-D = Victoria Symptom Validity Test Difficult Items Correct; WMT-IR = Word Memory Test Immediate Recognition; WMT-DR = Word Memory Test Delayed Recognition; WMT-C= Word Memory Test Consistency Index.

a = The following cutoffs were used to classify performance invalidity: < 17 correct on VSVT difficult items, or a DCT E-Score > 14, or < 82.5% correct on the immediate recognition or delayed recognition or consistency index of the WMT.

b =Mean testing interval was 34.4 days.

Table 2.

Means, SDs and percent of sample scoring at or below impaired rangea on neuropsychological tests (n = J08)b

Test Mean (SD) % Below 
LNS 10.73 2.35 4.6% 
TMT-A 20.28 7.48 1.8% 
TMT-B 49.11 16.28 5.4% 
Test Mean (SD) % Below 
LNS 10.73 2.35 4.6% 
TMT-A 20.28 7.48 1.8% 
TMT-B 49.11 16.28 5.4% 

Note. LNS = Age Corrected Scale Score on the Letter Number Sequencing Subtest of the Wechsler Adult Intelligence Scale- III; TMT-A = Trial Making Test Part A time in seconds; TMT-B = Trial Making Test Part B time in seconds.

a = Performing < 2 SDs below mean of normative sample according to age and education level. b = Mean testing interval was 34.4 days.

Table 3.

Means, SDs and percent of sample below cutoffsa by sex on motor tests

  Females (N = 82)   Males (N = 26)  
 Mean SD % Below Mean SD % Below 
FTDH 43.58 8.17 8.5% 52.67 6.92 7.6% 
FTNH 41.77 7.08 8.5% 50.81 6.96 3.8% 
GPDH 68.02 8.39 1.2% 74.04 6.93 0% 
GPNH 73.42 11.21 1.2% 77.58 7.21 0% 
  Females (N = 82)   Males (N = 26)  
 Mean SD % Below Mean SD % Below 
FTDH 43.58 8.17 8.5% 52.67 6.92 7.6% 
FTNH 41.77 7.08 8.5% 50.81 6.96 3.8% 
GPDH 68.02 8.39 1.2% 74.04 6.93 0% 
GPNH 73.42 11.21 1.2% 77.58 7.21 0% 

Note. FTDH = Finger Tapping Test Dominant Hand; FTNH = Finger Tapping Test Non-Dominant Hand; GPDH = Grooved Pegboard Test Dominant Hand; GPNH = Grooved Pegboard Test Non-Dominant Hand.

a = Performing ≤ 2 SDs below mean of normative sample according to age and education level.