To measure something

• changes over time
• changes over cross-sections

• Ideally, we want to count how much stuff we produced
• Alternatives
  • Sales, expenditures, employment

Major factors to consider:

• Industry
• Geography
• Recency
• Frequency

Two other relevant concepts

• Real versus nominal
• Seasonal adjustment

• U.S. Bureau of Economic Analysis for the national economy
• U.S. Census Bureau for the neighborhood level data
• data.gov for one-stop shop for the U.S. Government’s open data
• Headwater Economics to learn what data to use for each purpose and how to interpret them