Source: U.S. Census Bureau  

Release: Income and Poverty in the United States  

Units:  Current Dollars, Not Seasonally Adjusted

Frequency:  Annual

Household data are collected as of March.

As stated in the Census's "Source and Accuracy of Estimates for Income, Poverty, and Health Insurance Coverage in the United States: 2011" (http://www.census.gov/hhes/www/p60_243sa.pdf):

Estimation of Median Incomes. The Census Bureau has changed the methodology for computing median income over time. The Census Bureau has computed medians using either Pareto interpolation or linear interpolation. Currently, we are using linear interpolation to estimate all medians. Pareto interpolation assumes a decreasing density of population within an income interval, whereas linear interpolation assumes a constant density of population within an income interval. The Census Bureau calculated estimates of median income and associated standard errors for 1979 through 1987 using Pareto interpolation if the estimate was larger than $20,000 for people or $40,000 for families and households. This is because the width of the income interval containing the estimate is greater than $2,500.

We calculated estimates of median income and associated standard errors for 1976, 1977, and 1978 using Pareto interpolation if the estimate was larger than $12,000 for people or $18,000 for families and households. This is because the width of the income interval containing the estimate is greater than $1,000. All other estimates of median income and associated standard errors for 1976 through 2011 (2012 ASEC) and almost all of the estimates of median income and associated standard errors for 1975 and earlier were calculated using linear interpolation.

Thus, use caution when comparing median incomes above $12,000 for people or $18,000 for families and households for different years. Median incomes below those levels are more comparable from year to year since they have always been calculated using linear interpolation. For an indication of the comparability of medians calculated using Pareto interpolation with medians calculated using linear interpolation, see Series P-60, Number 114, Money Income in 1976 of Families and Persons in the United States (www2.census.gov/prod2/popscan/p60-114.pdf).

Source: U.S. Bureau of Economic Analysis  

Release: Personal Income and Outlays  

Units:  Index 2017=100, Seasonally Adjusted

Frequency:  Monthly

BEA Account Code: DPCERG

The Personal Consumption Expenditures Price Index is a measure of the prices that people living in the United States, or those buying on their behalf, pay for goods and services. The change in the PCE price index is known for capturing inflation (or deflation) across a wide range of consumer expenses and reflecting changes in consumer behavior. For example, if the price of beef rises, shoppers may buy less beef and more chicken.

The PCE Price Index is produced by the Bureau of Economic Analysis (BEA), which revises previously published PCE data to reflect updated information or new methodology, providing consistency across decades of data that's valuable for researchers. They also offer the series as a Chain-Type index, as above. The PCE price index is used primarily for macroeconomic analysis and forecasting.

The PCE Price index is the Federal Reserve’s preferred measure of inflation. The PCE Price Index is similar to the Bureau of Labor Statistics' consumer price index for urban consumers. The two indexes, which have their own purposes and uses, are constructed differently, resulting in different inflation rates.

For more information on the PCE price index, see:
U.S. Bureau of Economic Analysis, Guide to the National Income and Product Accounts of the United States (NIPA)
U.S. Bureau of Economic Analysis, Personal Consumption Expenditures Price Index
U.S. Bureau of Economic Analysis, Prices & Inflation
U.S. Bureau of Labor Statistics, Differences between the Consumer Price Index and the Personal Consumption Expenditure Price Index