The key objective of validation is to prove the diagnostic capability of the diagnostic questionnaire, and is necessary whenever diagnostic accuracy is important and diagnoses are not made by headache experts in face-to-face interviews.
Finding the smallest set of valid test configurations that ensure sufficient coverage of the system's feature interactions is thus the objective of validation engineers, especially when the execution of test configurations is costly or time-consuming.
The validation instrument also included explanations of the objectives of the validation exercise, the meaning of the elements used in the CLDs, and how to respond to the questions; see Additional file 4 for the validation instrument.
It was also decided that if that team felt that potential modifications in the questionnaire were relevant enough, data gathered from patients included in the pilot phase would not be used for the objectives of the validation phase.
We sent them a letter with the objectives of the validation study, an informed consent form and a contact information form (e-mail address, telephone number and hours to be called), together with a postage-paid envelope.
The specific objectives of this validation study were to not only verify the GP88 cut-off value, but also quantify GP88 performance, and test whether the information in GP88 duplicates or is additive to that found in covariates, such as age, PR expression, tumor size, tumor grade, lymph node status, disease stage and treatments.
The training programme should be standardised, include objective metrics of validation, offer universal accessibility and provide credentials to confirm successful training [23, 24, 25, 26, 27, 28].
Patients were offered telephone and email support throughout the treatment and therefore we hope to have optimised compliance however there was no specific objective way of validation.
While this may appear to be an objective method of validation, it is only pertinent to those patients who come to surgery or biopsy, and may be subject to sampling error.
The pivotal objective of the validation phase is to evaluate the clinical utility of the biomarker candidates [9].
