01
Data cleanup and reconciliation
Turn inconsistent exports, spreadsheets, or tables into a dependable dataset for analysis.
- Combining files from multiple sources
- Checking missing, duplicate, or conflicting values
- Reconciling definitions and totals
Independent data analyst · Concord, California
Clear analysis from complicated data.
I help teams clean and organize data, answer focused analytical questions, and build reporting workflows that can be used again.
Ways I can help
Common types of work
An engagement can cover one category or combine several. The scope is defined around the question, the available data, and the result you need—not a fixed package.
02
Analysis and decision support
Answer a focused business or research question with evidence that is clear about its limits.
- Exploratory and statistical analysis
- Trends, comparisons, and segmentation
- One-time questions that need a defensible answer
03
Reporting and repeatable workflows
Replace recurring manual steps with a process that can be run, checked, and updated again.
- Recurring reports and data refreshes
- Reusable queries or analysis scripts
- Documented procedures for future updates
04
Data organization and documentation
Make important data easier to understand, maintain, and hand off to the next person.
- Metric definitions and data dictionaries
- Database queries and table organization
- Method notes, assumptions, and lineage
Approach
Careful with the data. Practical about the outcome.
The goal is not just to produce an answer. It is to make clear what the answer is based on and leave the work in a usable state.
- 1
Clarify the decision
Start with the question, who will use the answer, and what a useful outcome looks like.
- 2
Check the evidence
Inspect the sources, resolve definitions, and document assumptions before drawing conclusions.
- 3
Deliver for reuse
Provide the result together with the method and documentation needed to understand or repeat it.
About
Zhihui Yang
Owner and Data Analyst
I am an independent data analyst whose work sits between analysis and data systems.
My background in Information Systems at Johns Hopkins University includes statistical analysis, database management, data analytics, and machine learning. I operate a sole proprietorship based in Concord, California and take on focused engagements in data analysis and data management.
I care about the less visible parts of analytical work: where the data came from, whether its definitions are consistent, how the result can be checked, and whether someone else can use the work after handoff.
Business structureSole proprietorship
LocationConcord, California
Client names, private datasets, and engagement details are not published without authorization. Examples on this site are generalized.
Contact
Have a data question or a workflow that needs attention?
Send a short note about the question, the data involved, and what you would like to be able to do when the work is complete.
zhihui@zhihuiyang.com