Many occupational therapists in South Africa and the United Kingdom are using the Vona du Toit Model of Creative Ability with its associated assessments and outcome measures in practice.  Although there appears to be strong clinical confidence in the use of these instruments that apply the levels of creative ability in the scoring system, little evidence has been published on the validity of the levels.To investigate three instruments based on the levels of creative ability: the Creative Participation Assessment (CPA), the Functional Levels Outcome Measure (FLOM) and the Activity Participation Outcome Measure (APOM) for evidence that the levels exist, represent increasing amounts of ability and that the scoring of the instruments follow a linear or hierarchical pattern. A secondary data analysis was conducted using threshold ordering of the Rasch Measurement Model to indicate whether the levels of creative ability exist. Data was previously collected in a study in 2001 (CPA) and during routine assessments in 2007 & 2008 (FLOM & APOM). Measures were used with a predominantly mental health population involving samples of 240 (CPA), 306 (FLOM) & 167 (APOM) within public and private settings. Results highlight the three measures showed perfect threshold ordering of categories, with no collapsing of items being necessary, indicating a linear or hierarchical ordering of scores. Results showed that all three instruments represent increasing amounts of ability in individuals and that the levels of creative ability do exist.  Although these findings are significant, it is the first in a series of analyses and the remaining assumptions in the Rasch Measurement Model still require testing for item functioning, local dependency between items uni-dimensionality and item-person fit.