Data is just recorded facts — but turning it into decisions is a career-defining skill. This guide gives you the language and a clear roadmap from beginner to employable data professional.
Types of data
- Structured — organised in rows and columns (databases, spreadsheets). Easy to query with SQL.
- Unstructured — text, images, emails, documents; no fixed format.
- Semi-structured — has some structure (JSON, CSV logs). And by nature:
- Quantitative (numbers you can measure — sales, counts) vs Qualitative (categories/descriptions — region, feedback).
- Discrete (whole counts) vs Continuous (any value in a range). Knowing the type tells you how to store, clean, analyse and visualise it.
Data quality — the foundation of trust
Analysis is only as good as the data. Watch for the dimensions of quality: accuracy, completeness, consistency, timeliness, validity and uniqueness (no duplicates). "Garbage in, garbage out" is the analyst's first law — most real work is cleaning and validating data before any analysis.
The data lifecycle
Data flows through stages: collect → store → clean/prepare → analyse → visualise/report → act → archive/delete. Analysts spend most time in clean/prepare and analyse; the value is delivered at report and act.
Your career roadmap
- Beginner — learn data types, quality and spreadsheets; understand the analysis process. Start as a Reporting/MI Analyst or Junior Data Analyst. Target Google Data Analytics or Power BI (PL-300).
- Intermediate — add SQL, visualisation & dashboards and practical statistics. Move into Data Analyst / BI Analyst / Insights Analyst.
- Advanced — automate pipelines and modelling; specialise. Progress to Senior Analyst, Analytics Engineer or Junior Data Engineer.
Put it to work
Pick one dataset you have access to and score it against the six quality dimensions — then practise analytics decisions in the Practical activities.
