Compare the system each role maintains
A data pipeline turns source records into a form someone can trust and use. A machine-learning system adds a model whose behavior depends on data, training choices and evaluation. The work overlaps where data quality affects model output.
Apache Airflow’s documentation is a primary reference for one workflow-orchestration tool. Google’s machine-learning engineering guidance discusses practical system concerns. Neither tool nor document defines every job carrying these titles.
Show reliability before complexity
| Data engineering evidence | ML engineering evidence |
|---|---|
| Input schema and quality checks | Clearly defined prediction task |
| Repeatable transformation | Training and evaluation separation |
| Safe rerun behavior | Baseline comparison and error analysis |
| Data lineage and access notes | Serving, monitoring and rollback plan |
This is an original comparison of project evidence. It is not a labor-market survey or a claim that one role is more senior.
For a demonstration, choose a licensed public dataset with a documented source. Preserve the raw input, record transformation steps and test what happens when a field is missing. A successful first run is insufficient if rerunning the pipeline duplicates the output.
Evaluate the model against the intended use
State the target, the baseline and the evaluation population. Keep test data separate from choices made during development. Examine error types, not only an aggregate score. A model that performs well on one dataset may fail when inputs change.
Do not present a tutorial score as evidence of real-world business impact. Explain the dataset’s limitations, any excluded groups and what remains untested. If the project uses a pretrained model, identify it and distinguish your contribution from the model provider’s work.
Read the ownership boundary in the vacancy
Ask whether the role owns ingestion, warehouses, training infrastructure, model selection, deployment or operational support. The answer determines which evidence to prioritize. A title alone will not tell you how much research or systems work is involved.
Use the portfolio guide to make the project reproducible and the language guide to choose tools by task. Compare the wider specializations if you are still deciding which part of the workflow interests you.
