Just for grins, I went to the website of my former employer to see what kind of visualizations they had, and there were two that I found interesting. I like these visualizations because they’re simple and straight forward, they use two or three variables and they tell compelling stories across a time frame.

Fannie Mae National Housing Survey

The first is the Fannie Mae Home Purchase Sentiment Index® (HPSI), because housing is a major part of the economy, this is an indicator of economic health. Here’s the link to the webpage with the animated visualization: National Housing Survey page.

This is a clean and simple visualization, displaying the frequency graphs of two categorical variables: is it a good time to buy a house and is it a good time to sell a house, with the x-axis spanning 36 months. The animation across the time axis makes it fun and interesting. You can see both lines take a dive in April 2020, when people were unsure what was going to happen due to Covid-19 restrictions.

What I like about this visualization is the ability to click on a single month and the animation will stop at that month, or back up to it. It’s fun to watch it “undo” itself. A screen capture of the graph at April 2020 is shown below,

The technical notes for the survey discusses the survey methodology, the sample design, data quality control and weighting. The sample size is approximately 1000 live phone interviews by land and cell phone, and the notes address the steps taken to help eliminate bias. Such as increasing the number cell phone interviews as cell phone usage has increased, conducting a percentage of interviews in Spanish only, weighting the data to the American Community Survey, and states that, “The margin of error for the total sample is +/-3.1 percent at the 95 percent confidence level and larger for sub-groups”.

Additionally, the About the National Housing Survey page provides links to the white paper for the survey, the questionnaire, current and archived data and a comparative assessment to other national surveys. So there is transparency provided into the process, results and analysis.

Housing Supply Graph

The housing supply graph is a two page visualization, which show a good summary of the housing market over the last two decades. The webpage is at this link: Single Family Starts…webpage.

The first page shows the housing starts, new homes being built in the U.S., in thousands of units. It combines a side-by-side bar chart for single-family and multifamily starts, with a line graph for total housing starts. The x-axis is divided yearly for a twenty year period. Tool tips on the bars and the graph display the housing start amount for that point on the graph.

The division of the data into single-family and multifamily shows the contribution of single-family starts to the housing bubble, and the steady rate of multifamily starts during most of the time frame. You can see the housing bubble peak in 2005, and the recession bottom out in 2009. And it shows that multifamily housing starts returned to pre-recession levels within five years. The screen capture for page 1 is shown below,

The second page is the existing housing supply graph, showing the number of months supply of existing homes based on realtor inventory to sales ratio. It’s a single line graph, with a tool tip that shows the ratio at finer granularity across the 20 year graph. It looks like the data may be in monthly or bi-monthly intervals, but you can’t tell because the tool tip label only shows the year. Adding the month to the label would be useful.

This is an inverse look at the housing market from the first page. With a little bit of awareness about the economy you can interpret the story behind this graph. There’s a sharp upward curve leading into the recession. Existing houses weren’t selling and inventory increased due to foreclosures and homeowners hoping to get out of expensive mortgages. Recovery is facilitated by low mortgage interest rates. There’s also a sharp spike in early 2020 at the start of Covid-19 restrictions but sales recovered quickly, interest rates are still low. Supply is at a 20 year low, are people keeping their homes because they don’t have to commute to work or school?