The Manchester Cough in Lung Cancer Scale: The Development and Preliminary Validation of a New Assessment Tool  Alex Molassiotis, RN, PhD, Jackie Ellis, BA (Hons), MSc, PhD, Richard Wagland, RN, BSc, MA, PhD, Mari Lloyd Williams, MD, FRCP, FRCGP, MMedSci, Chris D. Bailey, RN, BA (Hons), PhD, Richard Booton, MBChB, MRCP, PhD, Fiona Blackhall, FRCP, PhD, Janelle Yorke, RN, PhD, Jaclyn A. Smith, MBChB, MRCP, PhD  Journal of Pain and Symptom Management  Volume 45, Issue 2, Pages 179-190 (February 2013) DOI: 10.1016/j.jpainsymman.2012.01.015 Copyright © 2013 U.S. Cancer Pain Relief Committee Terms and Conditions

Fig. 1 a) Item Characteristic Curve for a nonfitting item: “Do you produce sputum when you cough?” The x-axis represents patient severity in logits (the log-odds of affirming an item) and the y-axis represents the value that a patient would be expected to score on this item. The curved line represents the expected scores for the item as defined by the Rasch model, and the dots represent the observed scores for the class intervals (patients placed into three groups according to their responses to all items combined) at the different severity levels. This item is under-discriminating; the observed scores (black dots) form a flatter curve than the expected scores. The fit residual (along the top) is 3.122 (requirement is ±2.5) and the Chi-square is P=0.05. This item was consequently removed. b) Item Characteristic Curve for a fitting item: “Does your coughing make you frustrated?” This item demonstrates good fit for each class interval; the observed scores (black dots) fall on the curve representing the expected scores. The fit residual (along the top) is −0.694 and the Chi-square is P = 0.17. This item was consequently retained. Journal of Pain and Symptom Management 2013 45, 179-190DOI: (10.1016/j.jpainsymman.2012.01.015) Copyright © 2013 U.S. Cancer Pain Relief Committee Terms and Conditions

Fig. 2 Example of a well-ordered transition between response categories for the item “Please rate how severe you think your cough is.” The y-axis represents the likelihood of a given response and the x-axis represents cough severity. The responses to this item fall in a logical progressive order; category responses represent an increase in cough severity (logits) for each category. For example, at the lowest patient severity (−4 logits), the probability of a score of 0 (i.e., “never”) is most likely, and at the highest patient severity (+4 logits), the probability of scoring a 5 (i.e., “all the time”) is most likely. Note: RUMM2020 allocates Category 1 (“never”) of the questionnaire to 0 (the blue line in the figure); Category 2 (“some of the time”) to 1; and so. Journal of Pain and Symptom Management 2013 45, 179-190DOI: (10.1016/j.jpainsymman.2012.01.015) Copyright © 2013 U.S. Cancer Pain Relief Committee Terms and Conditions

Fig. 3 Example of disordered threshold for the item “Do you have difficulty breathing when you cough?” At no patient severity, it is most likely that Category 1 (“some of the time”) will be scored, that is, even at the point where the probability of scoring a Category 1 is at its peak, it is still more likely that Category 0 will be scored instead. Similarly, at the more severe end of the scale, it is more likely that Category 5 will be scored instead of Category 4. Journal of Pain and Symptom Management 2013 45, 179-190DOI: (10.1016/j.jpainsymman.2012.01.015) Copyright © 2013 U.S. Cancer Pain Relief Committee Terms and Conditions

Fig. 4 Distribution of patients and item thresholds based on a Rasch logit scale. This figure shows the distributions of patient severity and item severity (locations) along the same linear scale measured in logits. Patients are on the upper part of the graph and item locations on the lower part. Most of the items are located between −2 and +2 logits. It can be seen that, on average, patients are at the milder end of the scale. Journal of Pain and Symptom Management 2013 45, 179-190DOI: (10.1016/j.jpainsymman.2012.01.015) Copyright © 2013 U.S. Cancer Pain Relief Committee Terms and Conditions