Reader Selection: 30 readers will be selected from the following five clinical specialty groups:

• emergency medicine (ED)
• adult intensive care (ICU)
• adult general medicine (AGM)
• radiographers (Rad)
• general radiologists

Each specialty group consists of 6 members of ranked seniority. For the physicians this consists of:

• Two 'Juniors' (Foundation Year 1 - Specialty Training 2 years)
• Two 'Middle Grades' (Registrar from Specialty Training 3 to 6 years)
• Two Consultants

For the radiographers, this consists of:

• Two 'Junior/Newly qualified radiographers' (up to 18 months experience post qualification)
• Two 'Mid-experience radiographers' (approx. 3 years' experience)
• Two 'Reporting radiographers' (5+ years' experience)

Two consultant thoracic radiologists. A third senior thoracic radiologist's opinion (>20 years experience) will undertake arbitration.

The reading will be done remotely via the Report and Image Quality Control site (www.RAIQC.com), an online platform allowing medical imaging viewing and reporting. Participants can work from any location, but the work must be done from a computer with internet access. For avoidance of doubt, the work cannot be performed from a phone or tablet.

The project is divided into two phases and participants are required to complete both phases. The estimated total involvement in the project is up to 20-24 hours.

Phase 1: Time allowed: 2 weeks

- Review 500 chest X-rays and express a clinical opinion through a structured reporting template (multiple choice, no open text required).

Rest/washout period of 2 weeks.

Phase 2 - Time allowed: 2 weeks

- Review 500 chest X-rays together with an AI report for each case and express your clinical opinion through the same structured reporting template used in Phase A.

Evaluation of the Lunit INSIGHT CXR algorithm will be performed comparing it to the reference standard in order to determine sensitivity.

Evaluation of the Lunit INSIGHT CXR algorithm will be performed comparing it to the reference standard in order to determine specificity.

Evaluation of the Lunit INSIGHT CXR algorithm will be performed comparing it to the reference standard. Continuous probability score from the algorithm will be utilized for the ROC analyses, while binary classification results with a predefined operating cut-off will be used for evaluation of sensitivity, specificity, positive predictive value, and negative predictive value.

The study will include two sessions (with and without AI overlay), with all 30 readers reviewing all 500 CXR cases each time separated by a washout period to mitigate recall bias. The cases will be randomised between the two reads and for every reader.

The study will include two sessions (with and without AI overlay), with all 30 readers reviewing all 500 CXR cases each time separated by a washout period to mitigate recall bias. The cases will be randomised between the two reads and for every reader.