Image provenance and the target label
Trace how dermatology images, labels, and patient groupings create the apparent prediction task.
A dermatology image dataset encodes acquisition device, lighting, magnification, body site, referral pathway, label process, and population. These variables can become shortcuts. Using only an approved deidentified public collection such as an ISIC benchmark, read its data dictionary and terms before downloading anything. Build a provenance table for a manageable subset: collection, image type, diagnosis label, label-confirmation method when available, patient or lesion identifier, age band, sex field, anatomic site, and missingness. Count images per patient and lesion. An image-level random split can leak the same lesion or patient into training and test sets, producing an optimistic estimate; use the strongest available grouping key. Inspect class balance and missing metadata without opening images first. Then view a random sample to identify rulers, ink markings, framing, and other acquisition cues. Do not relabel images or infer diagnoses. The output is a data audit that explains what the benchmark measures and which deployment population it cannot represent.
Try it yourself
- Read the dataset terms, medical disclaimer, and data dictionary.
- Create a metadata and missingness table for a small public subset.
- Check patient/lesion duplication and visually sample acquisition artifacts.
You’re ready to move on when…
- Dataset use complies with published terms and contains no local clinical data.
- Split unit is justified from available patient or lesion identifiers.
- Audit lists label source, missing fields, class balance, and visible shortcut risks.