PSYCHOMETRIC CONVERSION TABLE Standard Score
Percentile Rank
150
149
148
147
146
145
144
143
142
141
140
139
138
137
136
135
134
133
132
131
130
129
128
127
126
125
124
123
122
121
120
119
118
117
116
115
114
113
112
111
110
109
108
107
106
105
104
103
102
101
100
99
98
97
96
95
94
93
92
91
90
Michael Lee Zwiers, Ph.D., 2018
>99.9
>99.9
99.9
99.9
99.9
99.9
99.8
99.8
99.7
99.7
99.6
99.5
99
99
99
99
99
99
98
98
98
97
97
96
96
95
95
94
93
92
91
90
88
87
86
84
82
81
79
77
75
73
70
68
66
63
61
58
55
53
50
47
45
42
40
37
34
32
30
27
25
Scaled Score
19
18
17
16
15
14
13
12
11
10
9
8
T-Score
Z-Score
80
+3.0
78
+2.75
77
+2.67
75
+2.50
73
+2.33
72
+2.25
70
+2.00
68
+1.75
67
+1.67
5
+1.50
63
+1.33
62
+1.25
60
+1.00
58
+0.75
57
+0.67
55
+0.55
53
+0.33
52
+0.25
50
0.00
48
-0.25
47
-0.33
45
-0.50
43
-0.67
Description
WAA
Very Superior
WAA
Very Superior
WAA
Very Superior
WAA
Very Superior
WAA
Very Superior
WAA
Very Superior
WAA
Very Superior
WAA
Very Superior
WAA
Very Superior
WAA
Very Superior
WAA
Very Superior
WAA
Very Superior
WAA
Very Superior
WAA
Very Superior
WAA
Very Superior
WAA
Very Superior
WAA
Very Superior
WAA
Very Superior
WAA
Very Superior
WAA
Very Superior
WAA
Very Superior
Well Above Average
Well Above Average
Well Above Average
Well Above Average
Above Average
Above Average
Above Average
Above Average
Above Average
Above Average
Above Average
Above Average
Above Average
Above Average
Above Average
High Average
High Average
High Average
High Average
High Average
Average
Average
Average
Average
Average
Average
Average
Average
Average
Average
Average
Average
Average
Average
Average
Average
Average
Average
Average
Low Average
PSYCHOMETRIC CONVERSION TABLE Standard Score
Percentile Rank
89
88
87
86
85
84
83
82
81
80
79
78
77
76
75
74
73
72
71
70
69
68
67
66
65
64
63
62
61
60
59
58
57
56
55
54
53
52
51
50
<40
<20/25
Scaled Score
23
21
19
18
16
14
13
12
10
9
8
7
6
5
5
4
4
3
3
2
2
2
1
1
1
1
1
1
0.5
0.4
0.3
0.2
0.1
0.1
0.1
0.1
0.1
0.1
<0.1
<0.1
T-Score
7
6
5
4
3
2
1
42
-0.75
40
-1.00
38
-1.25
37
-1.33
35
-1.50
33
-1.67
32
-1.75
30
-2.00
28
-2.25
27
-2.33
25
-2.50
23
-2.67
22
-2.75
20
-3.00
Wechsler Tests
IQ
130 and above
120 – 129
110 – 119
90 – 109
80 – 89
70 – 79
69 and Below
Classification
Extremely High
Very High
High Average
Average
Low Average
Very Low
Extremely Low
Michael Lee Zwiers, Ph.D., 2018
Z-Score
Description
Low Average
Low Average
Low Average
Low Average
Below Average
Below Average
Below Average
Below Average
Below Average
Below Average
Below Average
Below Average
Below Average
Below Average
Below Average
Far Below Average
Far Below Average
Far Below Average
Far Below Average
FBA Mild (65/70 to 50/55)
FBA Mild (65/70 to 50/55)
FBA Mild (65/70 to 50/55)
FBA Mild (65/70 to 50/55)
FBA Mild (65/70 to 50/55)
FBA Mild (65/70 to 50/55)
FBA Mild (65/70 to 50/55)
FBA Mild (65/70 to 50/55)
FBA Mild (65/70 to 50/55)
FBA Mild (65/70 to 50/55)
FBA Mild (65/70 to 50/55)
FBA Mild (65/70 to 50/55)
FBA Mild (65/70 to 50/55)
FBA Mild (65/70 to 50/55)
FBA Mild (65/70 to 50/55)
Mod (50/55 to 35/40)
Mod (50/55 to 35/40)
Mod (50/55 to 35/40)
Mod (50/55 to 35/40)
Mod (50/55 to 35/40)
Mod (50/55 to 35/40)
Severe (35/40 to 20/25)
Profound (<20 or 25)
Stanford Binet
IQ
145 – 160
130 – 144
120 – 129
110 – 119
90 – 109
80 – 89
70 – 79
55 – 69
40 – 54
Classification
Very Gifted / Highly Advanced
Gifted / Very Advanced
Superior
High Average
Average
Low Average
Borderline Impaired / Delayed
Mildly Impaired or Delayed
Moderately Impaired / Delayed