Visualizing GDP: An Inside Look at the Q1 Advance Estimate
April 28, 2016
by Doug Short
Note: The charts in this commentary have been updated to include the Q1 2016 Advance Estimate.
The chart below is a way to visualize real GDP change since 2007. It uses a stacked column chart to segment the four major components of GDP with a dashed line overlay to show the sum of the four, which is real GDP itself. Here is the latest overview from the Bureau of Labor Statistics:
The increase in real GDP in the first quarter reflected positive contributions from personal consumption expenditures (PCE), residential fixed investment, and state and local government spending that were partly offset by negative contributions from nonresidential fixed investment, private inventory investment, exports, and federal government spending. Imports, which are a subtraction in the calculation of GDP, increased.
Let's take a closer look at the contributions of GDP of the four major subcomponents. The data source for this chart is the Excel file accompanying the BEA's latest GDP news release (see the links in the right column). Specifically, it uses Table 2: Contributions to Percent Change in Real Gross Domestic Product.
Note: The conventional practice is to round GDP to one decimal place, the latest at 0.5. The 0.54 GDP in the chart above is the real GDP calculated to two decimal places.
Over the time frame of this chart, the Personal Consumption Expenditures (PCE) component has shown the most consistent correlation with real GDP itself. When PCE has been positive, GDP has usually been positive, and vice versa. In the latest GDP data, the contribution of PCE came at 1.27 of the 0.54 real GDP. The contribution from PCE has been declining since Q2 of last year.
The contribution from Gross Private Domestic Investment dropped significantly from the previous quarter.
Net Exports, which is largely impacted by fluctuations in Dollar strength, is at a four-quarter low.
Here is a look at the contribution changes between over the past four quarters. The difference between the two rightmost columns was addressed in the BEA's GDP summary quoted above.
As for the role of Personal Consumption Expenditures (PCE) in GDP and how it has increased over time, here is a snapshot of the PCE-to-GDP ratio since the inception of quarterly GDP in 1947. To one decimal place, latest ratio of 69.0%. From a theoretical perspective, there is a point at which personal consumption as a percent of GDP can't really go any higher. We may be approaching that upper range.
Let's close with a look at the inverse behavior of three of the GPDI components during recessions. PCE and especially GC generally increase as a percent of GDP whereas GPDI declines. Note the three with different vertical axes (Personal Consumption Exependitures on the left, Gross Private Domestic Investment and Government Consumption on the right) to highlight the frequent inverse correlations.
The Second Estimate for Q1 GDP will be published on May 27.
Other GDP updates: