Userfriendly rescaling: zero point and unit 
Winsteps sets the zero point (local origin) at the mean item difficulty (including extreme items if UEXTREME=Yes). The unit of measurement is the logit. Changing the zero point and transforming logits into other units can be done with UIMEAN=, UPMEAN=, USCALE=. These transformed measurements can be more meaningful for particular applications, see Chapter 8 of BTD. Anchor values are treated according to UASCALE=
Example 0: we observe the (current mean) and (current S.D.) of a set of measures. We want (desired mean) and (desired S.D.) then
new USCALE = (current USCALE=) *(desired S.D.) / (current S.D.)
new UIMEAN = desired mean  (current mean  current UIMEAN=)*(new USCALE=) / (current USCALE=)
we observe the (current high) and (current low). We want (desired high) and (desired low) then
new USCALE = (current USCALE=) *(desired highdesired low)) / (current highcurrent low)
new UIMEAN = desired mean  (current mean  current UIMEAN=)*(new USCALE=) / (current USCALE=)
Example 1: CHIPs are a useful transformation, in which 1 logit = 4.55 CHIPs. In this userscaling system, standard errors tend to be about 1 CHIP in size. The recommended control variable settings are:
USCALE = 4.55
UIMEAN = 50
UDECIM = 1
MRANGE = 50
The probability structure of this relationship is:
Probability of Success
Difference between Person Ability Measure and Item Difficulty Measure in CHIPs
.10 10
.25 5
.50 0
.75 5
.90 10
Example 2: WITs are one tenth the size of CHIPs, enabling the elimination of decimals from your output tables.
USCALE = 45.5
UIMEAN = 500
UDECIM = 0
MRANGE = 500
Example 3: You want the lowest reportable person measure to be 0 and the highest to be 100. Looking at Table 20, you see the extreme values are 4.53 and +5.72. You have not used USCALE= and UIMEAN=, so the current values are USCALE=1, UIMEAN=0.
Therefore,
"wanted low" person measure = 0
"wanted high" person measure = 100
"wanted range" = "wanted high"  "wanted low" = 100  0 = 100
"current low" person measure = 4.53
"current high" person measure = 5.72
"current range" = "current high"  "current low" = 5.72  4.53 = 10.25
USCALE= (wanted range) / (current range) = 100 / 10.25 = 9.76
UIMEAN= ( wanted low )  ( current low * USCALE ) = 0  ( 4.53 * 9.76 ) = 44.20
Required values are:
USCALE = 9.76
UIMEAN = 44.20
UDECIM = 0 to show no decimal places in report
Double checking, when previous values are UIMEAN=0, USCALE=1:
low value = (current low)*(USCALE=) + (UIMEAN=) = (4.53 * 9.76) + 44.20 = 0.01 = 0
high value = (current high)*(USCALE=) + (UIMEAN=) = (5.72 * 9.76) + 44.20 = 100.02  100
Example 4: You want the lowest reportable person measure to be 0 and the highest to be 100. Looking at Table 20, you see the extreme values are 4.53 and +5.72. The current values are USCALE=2, UIMEAN=1.5
Therefore,
"wanted low" person measure = 0
"wanted high" person measure = 100
"wanted range" = "wanted high"  "wanted low" = 100  0 = 100
"current low" person measure = 4.53
"current high" person measure = 5.72
"current range" = "current high"  "current low" = 5.72  4.53 = 10.25
"current UIMEAN" = 1.5
"current USCALE" = 2
USCALE= [(wanted range) / (current range)]/(current USCALE) = [100 / 10.25]/2 = 9.76/2 = 4.88
UIMEAN= ( wanted low )  [(current lowcurrent UIMEAN) * USCALE ] = 0  [( 4.531.5) * 9.76] = 58.85
Required values are:
USCALE = 4.88
UIMEAN = 58.85
UDECIM = 0 to show no decimal places in report
Double checking is most easily done by looking at the new Table 20.
Example 5: You want the lowest reportable person measure to be 100 and the highest to be 900. Looking at Table 20, you see the extreme values are 4.53 and +5.72. Looking at the second page of output, you see the current values are USCALE=1 and UMEAN=0.
USCALE= (previous USCALE=) * (wanted range: 900  100) / (reported range: 5.72  4.53) = 1 * 800 / 10.25 = 78.05
UMEAN= (wanted low)  (reported low  previous UMEAN=)*(wanted range)/(reported range) = 100  (4.53  0)*800/10.25 = 453.56
UDECIM = 0 to show no decimal places in report
Example 6: You want normreferenced userscaling, such that the person mean is 0.0, and the person standard deviation is 1.0.
In a standard analysis, set:
UDECIM=4
USCALE=1
UMEAN=0
Look at Table 18
+
ENTRY RAW
NUMBER SCORE COUNT MEASURE

 MEAN 6.7 14.0 .3728
 P.SD 2.4 .0 2.2202
+
Set (either in a new analysis, or using the "Specification" pulldown menu
USCALE = 1/person S.D. = 1/2.2202 = 0.4504
UMEAN =  person mean/person S.D. =  (.3728)/2.2202 = 0.1679
Look at Table 18
+
ENTRY RAW
NUMBER SCORE COUNT MEASURE

 MEAN 6.7 14.0 .0000
 P.SD 2.4 .0 1.0000
+
Example 7: You want to give your passfail point the value 400 and 100 to the lowest reported measure. Inspecting your output you see that the passfail point is at 1.5 logits, and that 3.3 logits is the lowest reported measure.
Then 400100 new units = 1.5  (3.3) logits, so
USCALE = 300 / 4.8 = 62.5
UMEAN = 400  (1.5) * 62.5 = 306.25
Then: 1.5 logits = 306.25 + 1.5*62.5 = 400
3.3 logits = 306.25  3.3*62.5 = 100
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