title: Development and validation of the nasopharyngeal cancer scale among the system of quality of life instruments for cancer patients (QLICP-NA V2.0): combined classical test theory and generalizability theory.
abstract: This research was designed to develop a nasopharyngeal cancer (NPC) scale based on quality of life (QOL) instruments for cancer patients (QLICP-NA). This scale was developed by using a modular approach and was evaluated by classical test and generalizability theories.
  
  
  
  Programmed decision procedures and theories on instrument development were applied to create QLICP-NA V2.0. A total of 121 NPC inpatients were assessed using QLICP-NA V2.0 to measure their QOL data from hospital admission until discharge. Scale validity, reliability, and responsiveness were evaluated by correlation, factor, parallel, multi-trait scaling, and t test analyses, as well as by generalizability (G) and decision (D) studies of the generalizability theory.
  
  
  
  Results of multi-trait scaling, correlation, factor, and parallel analyses indicated that QLICP-NA V2.0 exhibited good construct validity. The significant difference of QOL between the treated and untreated NPC patients indicated a good clinical validity of the questionnaire. The internal consistency (α) and test-retest reliability coefficients (intra-class correlations) of each domain, as well as the overall scale, were all >0.70. Ceiling effects were not found in all domains and most facets, except for common side effects (24.8 %) in the domain of common symptoms and side effects, tumor early symptoms (27.3 %) and therapeutic side effects (23.2 %) in specific domain, whereas floor effects did not exist in each domain/facet. The overall changes in the physical and social domains were significantly different between pre- and post-treatments with a moderate effective size (standard response mean) ranging from 0.21 to 0.27 (p < 0.05), but these changes were not obvious in the other domains, as well as in the overall scale. Scale reliability was further confirmed by G coefficients and index of dependability, with more exact variance components based on generalizability theory.
  
  
  
  QLICP-NA V2.0 exhibited reasonable degrees of validity, reliability, and responsiveness. However, this scale must be further improved before it can be used as a practical instrument to evaluate the QOL of NPC patients in China.
authors.affiliation: Nutritional Department, The Affiliated Hospital of Guangdong Medical College, Zhanjiang, 524001, Guangdong, China.
authors.forename: Jiayuan
authors.initials: J
authors.lastname: Wu
authors.affiliation: School of Pubic Health, Guangdong Medical College, Zhanjiang, 524023, Guangdong, China.
authors.forename: Liren
authors.initials: L
authors.lastname: Hu
authors.affiliation: School of Pubic Health, Guangdong Medical College, Zhanjiang, 524023, Guangdong, China.
authors.forename: Gaohua
authors.initials: G
authors.lastname: Zhang
authors.affiliation: Department of Oncology, The Affiliated Hospital of Guangdong Medical College, Zhanjiang, 524001, Guangdong, China. lianqilian@gdmc.edu.cn.
authors.forename: Qilian
authors.initials: Q
authors.lastname: Liang
authors.affiliation: School of Public Health, Kunming Medical University, Kunming, 650500, Yunnan, China.
authors.forename: Qiong
authors.initials: Q
authors.lastname: Meng
authors.affiliation: School of Humanities and Management, Research Center on Quality of Life and Applied Psychology, Guangdong Medical College, Dongguan, 523808, Guangdong, China. wanchh@hotmail.com.
authors.forename: Chonghua
authors.initials: C
authors.lastname: Wan
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000503:physiopathology / Q000523:psychology*; D011594:Psychometrics / Q000379:methods*; D015203:Reproducibility of Results; D018434:Sickness Impact Profile; D011795:Surveys and Questionnaires; D055815:Young Adult
keywords: Classical test theory; Generalizability theory; Nasopharyngeal cancer; Quality of life; Standardized response mean