Although the Jackson/Cubbin pressure ulcer (PU) risk scale performs best among risk scales used in intensive care units (ICUs), its performance was not fully satisfactory. In 2010, a minimally modified Jackson/Cubbin (mJ/C) PU risk scale was introduced to formalize PU risk assessment in a large medical-surgical ICU in Finland. The purpose of this secondary analysis was to examine whether individual categories of the mJ/C scale have similar weight and whether the scores within each category (from 1 to 4; 1 equaling highest risk and 4 equaling lowest risk) are linear, as is assumed for the original and modified scales. Using data from a cohort of 1,616 consecutively admitted patients retrieved from the ICU database, a detailed secondary analysis of each of the 12 main scoring categories of the Jackson/Cubbin risk scale was performed using logistic regression and analysis of linearity and weight. Of the 1,616 admitted patients, 168 developed a PU during their ICU stay. Among the risk categories, body mass index, nutrition, respiration, age, and transportation during the 48 hours before scoring did not contribute significantly (P > 0.05) to the total risk score or the actual development of a PU. The 7 other main categories - incontinence, mobility, medical history, oxygen requirement, need for assistance with hygiene, hemodynamics, and general skin condition - were the main risk contributors. Although only the linearity of the different categories correlated significantly with the predictive value of the categories, the linearity as well as the weights of the categories were at variance from what was assumed originally. The mJ/C scale needs refinement to be a more accurate instrument for PU risk assessment of ICU patients. Not all mJ/C categories were found to contribute to the risk and, when they do, their weight and linearity vary from what has been assumed. The categories respiration and oxygen requirement and the categories mental condition, mobility, and hygiene may overlap. The importance of the incontinence category depends on the frequency of urinary and fecal incontinence management system usage. A simpler, more valid and more sensitive risk assessment scale than the current Jackson/Cubbin scale is needed for ICU patients.