Data Skills
Data Analyst vs Data Scientist vs Data Engineer: What Each Role Actually Does
A practical comparison of three data careers, their deliverables, collaboration patterns, and ways to test which work fits you.

Data Skills
Understand how dbt models, tests, documentation, and version control help teams turn warehouse data into maintainable analytics.
Analytics engineering connects warehouse data to trusted analytical models. Raw operational data often has inconsistent names, duplicated business logic, and unclear grain. dbt provides a way to organize SQL transformations as a project with dependencies, tests, and documentation; it does not remove the need to understand the data.
Start with a question and a small set of source tables. Write down what each source row represents and who owns its meaning. Your first goal is a model that a downstream analyst can understand, not an elaborate project structure copied from an unrelated production system.
A common pattern separates source-aligned staging models from intermediate logic and consumer-facing models. Staging can standardize names and types; intermediate models can express reusable business logic; final models can present a stable analytical shape. The exact layering should fit project complexity rather than become ceremony.
Name models and columns consistently, and keep transformations focused. Use refs to express dependencies between models so the project graph reflects the actual workflow. Avoid duplicating definitions of the same metric across downstream files; centralizing logic makes review and change safer.
Declare upstream sources with useful descriptions and freshness expectations where appropriate. Source definitions clarify where data originates and make lineage visible. Freshness checks require a meaningful update expectation; they are not a generic badge that guarantees data quality.
Document key fields and explain the business meaning of important columns. When an upstream table changes, lineage helps identify affected models. Record the original source and its permission terms, especially when a project is public. Never expose credentials or private warehouse identifiers in a portfolio.

Built-in tests and custom data tests can express assumptions such as non-null keys, uniqueness, accepted values, or relationships. Select checks based on the meaning and risk of each model. A test can pass while the business definition is wrong, so technical validation must complement stakeholder review.
Include failure examples in your development process: what happens when a key is duplicated or a category changes? Decide whether the model should fail, warn, or route the anomaly for investigation. Tests are most valuable when they communicate a specific expectation and lead to a useful response.

Provide a README with project structure, prerequisites, profile setup using safe placeholders, commands, sample models, and expected outputs. State which warehouse or adapter is required and what reviewers can run locally. Do not commit secrets, actual customer data, or machine-specific configuration.
Keep model SQL readable and include a small diagram or description of dependencies. Demonstrate a source, staging model, transformation, final model, and relevant tests. If a warehouse is unavailable to reviewers, include an illustrative result while clearly distinguishing it from a live execution.
Analytics engineering is collaborative: definitions need agreement among analysts, domain experts, and data producers. Include a brief decision log for a metric with competing interpretations. Explain who should approve changes and what downstream users could be affected.
For your next step, choose a public dataset, model it into a clear fact-and-dimension structure, add meaningful tests, and ask someone to interpret the output without your help. Their questions will reveal gaps in naming and documentation. Present the trade-offs honestly instead of claiming production readiness.
Career examples are guidance, not vacancy announcements or job guarantees. Confirm requirements, regional access and current product terms at the linked official source.
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A practical comparison of three data careers, their deliverables, collaboration patterns, and ways to test which work fits you.
Data Skills
A step-by-step guide to showcasing SQL reasoning, reproducibility, and business interpretation in portfolio projects.
Data Skills
Turn spreadsheet work into clear evidence of data cleaning, analysis, validation, and communication.