## 2 Methodology
### Study Design  
Two online questionnaires, administered via the RedCap platform, were used to investigate the potential benefits and impact on patients who presented for lung function testing at a mobile service. Lung function testing was conducted by an experienced respiratory scientist employed by the mobile lung function testing clinic and involved various tests including spirometry, lung volume and diffusion capacity testing. Lung function testing results were analysed by a respiratory physician associated with the mobile lung function testing clinic and a report was forwarded to the patient's GP.  
The two questionnaires, a baseline questionnaire and a 6-8 week follow-up questionnaire, were developed using a mixed methods format including a combination of previously validated tools along with demographic and medical history questions. Validated tools incorporated into the questionnaires included the asthma control test (ACT) [10], COPD assessment test (CAT) [11], the clinical COPD questionnaire (CCQ) [12] and the St George's respiratory questionnaire (SGRQ) [13] Permission was sought and granted to use these validated tests.  
Briefly, the ACT contained five items with a four week recall on symptoms and daily functioning. Each item was scored from 1 to 5. The ACT overall scores ranged from 5 (poorly controlled asthma) to 25 (completely controlled asthma), with an ACT >19 indicating well-controlled asthma. The CAT, which assessed the impact of COPD on current health status, consisted of eight items, each scored between 0 and 5. Scoring involved adding the scores of the eight individual items to provide a total score out of 40. Higher scores represented a greater negative impact on disease. The CCQ consisted of 10 items, and all scores ranged from zero to six (0 = no impairment, 6 = worst score). The three domains of the CCQ included symptoms (4 items), functional state (4 items) and mental state (2 items). The recall period was seven days. The SGRQ, an airway disease-specific questionnaire to measure the impact on overall health, consisted of 50 items and three domains. Domains included symptoms (8 items), activity (16 items) and impacts (26 items). Each score ranged from 0 to 100% (with higher scores indicating more limitations).  
One of the investigators recruited patients and collected data at each lung function testing site. They assisted with the administration of the baseline questionnaire's completion using an iPad. An automated follow-up email was sent to participants after 6-8 weeks via REDCap(r), inviting them to complete the follow-up questionnaire. Participants unable to access the questionnaire electronically were invited to complete the same questionnaire as a telephone interview. Non-responders were telephoned two weeks after the link to the follow-up questionnaire becoming available to them. Participants who completed the baseline and follow-up questionnaire were offered an AUD 50 gift card as a token of appreciation of their time.  
The GP questionnaire collected demographic data (age, gender, years of general practice, etc.), and asked GPs about their awareness, and usefulness, of the lung function testing service and respiratory physician's subsequent report. GPs were also asked to provide information about any actions/intentions in response to the respiratory physician's report/s following testing. The study aimed to recruit 20 GPs. GPs who agreed to participate were offered an AUD 50 gift card as a token of appreciation for their time.