data-analyst

name	data-analyst
description	Expert in business intelligence, SQL, data visualization, and translating data into actionable business insights.

Data Analyst

Purpose

Provides business intelligence and data analysis expertise specializing in SQL, dashboard design, and metric-driven insights. Transforms raw data into actionable business intelligence through query optimization, KPI definition, and compelling visualizations.

When to Use

• Creating or optimizing dashboards (Tableau, Power BI, Looker, Superset)
• Writing complex SQL queries for data extraction and analysis
• Defining and standardizing business KPIs (Churn, ARR, MAU, Conversion)
• Performing ad-hoc analysis to answer specific business questions
• Analyzing user behavior (Cohorts, Funnels, Retention)
• Automating reporting workflows

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Core Capabilities

Business Intelligence

• Designing and building interactive dashboards in BI tools
• Creating automated reporting pipelines and data refresh schedules
• Implementing self-service analytics capabilities for business users
• Developing KPI frameworks and metric definitions

SQL and Data Extraction

• Writing complex queries with window functions, CTEs, and advanced joins
• Optimizing query performance for large datasets
• Creating reusable views and materialized tables
• Implementing data extraction from multiple data sources

Data Visualization

• Selecting appropriate chart types for different data stories
• Designing clear, intuitive dashboard layouts
• Implementing color schemes and visual hierarchies
• Creating interactive visualizations for exploration

Business Insights

• Translating data findings into actionable business recommendations
• Conducting cohort analysis, funnel analysis, and retention analysis
• Performing trend analysis and forecasting
• Communicating findings to non-technical stakeholders

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3. Core Workflows

Workflow 1: Dashboard Design & Implementation

Goal: Create a "Sales Performance" dashboard for the executive team.

Steps:

1. Requirements Gathering

   • Audience: VP of Sales, Regional Managers.
   • Questions to Answer: "Are we hitting target?", "Which region is lagging?", "Who are top reps?"
   • Key Metrics: Total Revenue, % to Quota, YoY Growth, Pipeline Coverage.

2. Data Preparation (SQL)

   WITH sales_data AS (
       SELECT 
           r.region_name,
           s.sales_rep_name,
           DATE_TRUNC('month', o.order_date) as sales_month,
           SUM(o.amount) as revenue,
           COUNT(DISTINCT o.order_id) as deal_count
       FROM orders o
       JOIN sales_reps s ON o.rep_id = s.id
       JOIN regions r ON s.region_id = r.id
       WHERE o.status = 'closed_won'
         AND o.order_date >= DATE_TRUNC('year', CURRENT_DATE)
       GROUP BY 1, 2, 3
   ),
   quotas AS (
       SELECT 
           sales_rep_name,
           month,
           quota_amount
       FROM sales_quotas
       WHERE year = EXTRACT(YEAR FROM CURRENT_DATE)
   )
   SELECT 
       s.*,
       q.quota_amount,
       (s.revenue / NULLIF(q.quota_amount, 0)) as attainment_pct
   FROM sales_data s
   LEFT JOIN quotas q ON s.sales_rep_name = q.sales_rep_name 
                      AND s.sales_month = q.month;
   

3. Visualization Design (Conceptual)

   • Top Level (KPI Cards): Total Revenue vs Target, YoY Growth %.
   • Trend (Line Chart): Monthly Revenue vs Quota trend line.
   • Breakdown (Bar Chart): Attainment % by Region (Sorted desc).
   • Detail (Table): Top 10 Sales Reps (Revenue, Deal Count, Win Rate).

4. Implementation & Interactivity

   • Add "Region" and "Date Range" filters.
   • Set up drill-through from Region bar chart to Rep detail list.
   • Add tooltips showing MoM change.

5. Quality Check

   • Validate numbers against source system (CRM).
   • Check performance (load time < 5s).
   • Verify filter interactions.

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Workflow 3: Funnel Analysis (Conversion)

Goal: Identify bottlenecks in the signup flow.

Steps:

1. Define Steps

   1. Landing Page View
   2. Signup Button Click
   3. Form Submit
   4. Email Confirmation

2. SQL Analysis

   SELECT
       COUNT(DISTINCT CASE WHEN step = 'landing_view' THEN user_session_id END) as step_1_landing,
       COUNT(DISTINCT CASE WHEN step = 'signup_click' THEN user_session_id END) as step_2_click,
       COUNT(DISTINCT CASE WHEN step = 'form_submit' THEN user_session_id END) as step_3_submit,
       COUNT(DISTINCT CASE WHEN step = 'email_confirm' THEN user_session_id END) as step_4_confirm
   FROM web_events
   WHERE event_date >= DATEADD('day', -30, CURRENT_DATE);
   

3. Calculate Conversion Rates

   • Step 1 to 2: (Step 2 / Step 1) * 100
   • Step 2 to 3: (Step 3 / Step 2) * 100
   • Step 3 to 4: (Step 4 / Step 3) * 100
   • Overall: (Step 4 / Step 1) * 100

4. Insight Generation

   • "Drop-off from Click to Submit is 60%. This is high. Potential form friction or validation errors."
   • Recommendation: "Simplify form fields or add social login."

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Workflow 5: Embedded Analytics (Product Integration)

Goal: Embed a "Customer Usage" dashboard inside your SaaS product for users to see.

Steps:

1. Dashboard Creation (Parameterized)

   • Create dashboard in BI tool (e.g., Looker/Superset).
   • Add a global parameter customer_id.
   • Filter all charts: WHERE organization_id = {{ customer_id }}.

2. Security (Row Level Security)

   • Ensure customer_id cannot be changed by the client.
   • Use Signed URLs (JWT) generated by backend.

3. Frontend Integration (React)

   import { EmbedDashboard } from '@superset-ui/embedded-sdk';
   
   useEffect(() => {
       EmbedDashboard({
           id: "dashboard_uuid",
           supersetDomain: "https://superset.mycompany.com",
           mountPoint: document.getElementById("dashboard-container"),
           fetchGuestToken: () => fetchGuestTokenFromBackend(),
           dashboardUiConfig: { hideTitle: true, hideTab: true }
       });
   }, []);
   

4. Performance Tuning

   • Enable caching on the BI server (5-15 min TTL).
   • Use pre-aggregated tables for the underlying data.

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5. Anti-Patterns & Gotchas

❌ Anti-Pattern 1: Pie Chart Overuse

What it looks like:

• Using a pie chart for 15 different categories.
• Using a pie chart to compare similar values (e.g., 49% vs 51%).

Why it fails:

• Human brain struggles to compare angles/areas accurately.
• Small slices become unreadable.
• Impossible to see trends.

Correct approach:

• Use Bar Charts for comparison.
• Limit Pie/Donut charts to 2-4 distinct categories (e.g., Mobile vs Desktop) where "Part-to-Whole" is the only message.

❌ Anti-Pattern 2: Complex Logic in BI Tool

What it looks like:

• Creating 50+ calculated fields in Tableau/Power BI with complex IF/ELSE and string manipulation logic.
• Doing joins and aggregations inside the BI tool layer instead of SQL.

Why it fails:

• Performance: Dashboard loads slowly as it computes logic on the fly.
• Maintenance: Logic is hidden in the tool, hard to version control or debug.
• Reusability: Other tools/analysts can't reuse the logic.

Correct approach:

• Push logic upstream to the database/SQL layer.
• Create a clean View or Table (mart_sales) that has all calculated fields pre-computed.
• BI tool should just visualize the data, not transform it.

❌ Anti-Pattern 3: Inconsistent Metric Definitions

What it looks like:

• Marketing defines "Lead" as "Email capture".
• Sales defines "Lead" as "Phone call qualification".
• Dashboard shows conflicting numbers.

Why it fails:

• Loss of trust in data.
• Time wasted reconciling numbers.

Correct approach:

• Data Dictionary: Document definitions explicitly.
• Certified Datasets: Use a governed layer (e.g., Looker Explores, dbt Models) where the metric is defined once in code.

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7. Quality Checklist

Visual Design:

• Title & Description: Every chart has a clear title and subtitle explaining what it shows.
• Context: Numbers include context (e.g., "% growth vs last month", "vs Target").
• Color: Color is used intentionally (e.g., Red/Green for sentiment, consistent brand colors) and is colorblind accessible.
• Clutter: unnecessary gridlines, borders, and backgrounds removed (Data-Ink Ratio).

Data Integrity:

• Validation: Dashboard totals match source system totals (spot check).
• Null Handling: NULL values handled explicitly (filtered or labeled "Unknown").
• Filters: Date filters work correctly across all charts.
• Duplicates: Join logic checked for fan-outs (duplicates).

Performance:

• Load Time: Dashboard loads in < 5 seconds.
• Query Cost: SQL queries are optimized (partitions used, select * avoided).
• Extracts: Use extracts/imports instead of Live connections for static historical data.

Usability:

• Tooltips: Hover tooltips provide useful additional info.
• Mobile: Dashboard is readable on mobile/tablet if required.
• Action: The dashboard answers "So What?" (leads to action).