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Table 4 Construction of scales with factor solutions and reliability analysis of 20 interview-based items

From: A patient perspective on shared decision making in stage I non-small cell lung cancer: a mixed methods study

  Factor loading ITCa α if item deleted
Do you think it is important for your decision that…    
Construct 1: Guidance by the clinician (α = .741)    
… your clinician gives you advice about the best treatment option for you? .850 .566 .656
… the treatment that best fits for you is chosen? .562 .590 .646
… you ask the questions you have? .528 .572 .669
Construct 2: Conduct of clinician (α = .774)    
your clinician takes you seriously? .866 .677 .683
… your clinician takes time for you? .828 .723 .651
… your clinician takes your treatment preferences seriously? .591 .479 .800
… your clinician provides opportunity to ask questions? .444 .514 .751
Construct 3: Preparation for treatment decision making (α = .864)    
… you receive information from your clinician about all possible treatment options? .847 .741 .827
… you receive information from your clinician about your disease? .832 .584 .856
… you follow your clinician in the proposed treatment advice? .781 .767 .823
… you decide together with your clinician about your treatment? .761 .675 .839
… your clinician asks you what you think of the different treatment options? .594 .643 .849
… your clinician gives you information about your disease that is understandable? .539 .611 .852
Construct 4: Active role of patient in treatment decision making (α = .782)    
… you receive time from your clinician to think about what treatment you want to have? .720 .706 .697
… you search for information (for example on the Internet) about possible treatment options? .695 .398 .798
… you eventually decide with your family what treatment you want to have? .665 .631 .715
… your clinician lets you decide what treatment you want to undergo? .522 .539 .747
… your clinician asks you about your situation at home? .494 .551 .744
  1. aItem Total Correlation
  2. The suitability of data for factor analysis was assessed by inspection of the correlation matrix, by computing the Kaiser-Meyer-Olkin measure of sampling adequacy value (KMO) and by running the Bartlett’s Test of Sphericity. KMO was .774 and Bartlett’s Test of Sphericity was < .00. KMO values of .60 or greater and a significant Bartlett’s Test of Sphericity for factor analysis were considered appropriate. An eigenvalue of 1.00 or greater was adopted as cut-off point to determine the number of components. An item’s factor loading of > .4 was used as a cut-off point for inclusion, followed reliability evaluation by calculations of Cronbach’s alpha