Item map for Independence domain. X = one subject; M = mean; S = one standard deviation from mean; T = two standard deviations from mean. The item positions for the five items in the independence domain appear on the right of the vertical dashed line. The person positions appear on the left of the line. Recall the five response options: (1)"Strongly disagree" (2)"Disagree somewhat" (3)"Neither disagree nor agree" (4)"Agree somewhat" and (5)"Strongly agree." Each item appears four times at logit positions that mark transitions between adjacent response options. The numbers in parentheses connote the adjacent response options. Thus, consider "Ask for help(1-2)" at the lowest (easiest) location on the map: this is the location where the likelihood that a subject would respond (2)"Disagree somewhat" to this item becomes greater than the likelihood he would respond (1)"Strongly disagree" to this item. The most difficult item from this domain (located at the top of the map) is "Give up control." The map is designed such that mean item location (difficulty) is at 0 logits (notice the "M" on the right side of the vertical line). Mean person location (ability, indicated by the "M" on the left side of the vertical line) is lower on the vertical line (i.e., fewer logits) than the mean item difficulty, thus indicating that item difficulty is slightly greater than person ability.