Table 1.

The Steps of Development and Testing the Instrument Organ Transplant Symptom and Wellbeing Instrument (OTSWI) Suggested by Juniper, Guyatt and Jaeschke [27]

A. Development
Step	Task	Performance
1	Specifying measurement goals	OTSWI was developed to be used for adult persons waiting for or have undergone solid organ transplantation (OT). They should be able to read and write Swedish or any other relevant language that the instrument is translated to. The primary purpose of the instrument is to be discriminative and evaluative. All areas of dysfunction associated with solid OT are included. The instrument is supposed to be self -administered, but will also be suitable for telephone interviews.
2	Item generation	Item pool was chosen from unstructured interviews, studies regarding health related quality of life (HRQOL), review of the transplant specific literature; discussions with transplant professionals and finally a review of generic HRQOL instruments.
4	Item reduction	The initial version included in a total 51 items. There were 28 items focused on symptoms, 8 items on physical functioning, 8 on emotional aspects and 7 items on social and financial aspects. The items were reduced by factor analysis based at 185 organ transplant recipients reported in Table 2. Finally the items were grouped into domains and labelled by a combination of their content, clinical experience and common sense.
4	Questionnaire formatting	Words were used that apply to the widest range of cultures and geographic areas in order to facilitate translation and widespread use. Each response relates to how much the problem or situation discomforts you, assessed on a five-point scale ranging from “not at all”(0), “a little”(1), “somewhat”(2), “quiet a bit”(3) and “very much” (4). Time was specified to a time frame of one week.
B. Testing
5	Pretesting	A small pretest was performed involving ten organ transplant recipients (OTR).
6	Reliability	Scale reliability was estimated using the Cronbach’s alpha. Reliability in terms of the relationship between the signal, in this case the difference between subjects, and the noise, the difference within a subject when the clinical state is stable will be tested by further research.
7	Responsiveness	To test if the instrument is responsive to the true change occurring in a patient over a period of time further research will be needed.
8	Validity	Validity was determined by the confirmatory multi-trait analysis program and by explorative principal component analysis (with oblique, varimax rotation). Construct validity was determined by examining the relation between OTSWI and the generic HRQOL-instrument SF-36.
9	Interpretability	We will use the so called anchor-based approach, where the changes in quality of life measures are compared, or anchored to other clinically meaningful outcomes. This will be tested further. In this study clinically meaningful outcomes were considered to be time since transplantation, number of graft rejections, type of organ and graft function at the time of the data collection.