This post is about a much discussed question: How did the Great Recession affect U.S. public libraries? I’m not really going to answer the question, as that would amount to a lengthy journal article or two. But I am going to suggest a way to approach the question using data from the Institute of Museum and Library Services (IMLS) Public Libraries in the United States Survey. Plus I’ll be demonstrating a handy data visualization tool known as a trellis chart that you might want to consider for your own data analysis tasks. (Here are two example trellis charts in case you’re curious. They are explained futher on.)
As for the recession question, in the library world most of the discussion has centered on pronouncements made by advocacy campaigns: Dramatic cuts in funding. Unprecedented increases in demand for services. Libraries between a rock and hard place. Doing more with less. And so forth.
Two things about these pronouncements make them great as soundbites but problematic as actual information. First, the pronouncements are based on the presumption that looking at the forest—or at the big picture, to mix metaphors—tells us what we need to know about the trees. But it does not.
In the chart below you can see that the Great Recession had no general, across-the-board effect on public library funding. Some libraries endured severe funding cuts, others more moderate cuts, others lost little or no ground, and the majority of libraries actually had funding increases in the aftermath of the recession.
Bars to the left of the zero line reflect libraries with decreases; bars to the right, increases. Change of -10% = 10% decrease. Change of 10% = 10% increase. Click for larger image.
In the chart note that 35% of libraries had 5-year inflation-adjusted cumulative decreases of one size or another. Of these libraries, about half (18% of all libraries) had decreases of 10% or greater and half (17% of all libraries) had decreases less than 10%. 65% of libraries had cumulative increases of any size. Of libraries with increases, two-thirds (43% of all libraries) had increases of 10% or greater and one-third (22% of all libraries) with increases less than 10%. By the way, expenditure data throughout this post are adjusted for inflation because using unadjusted (face-value) figures would understate actual decreases and overstate actual increases.1
The second problem with the advocacy pronouncements as information is their slantedness. Sure, library advocacy is partial by definition. And we promote libraries based on strongly held beliefs about their benefits. So perhaps the sky-is-falling messages about the Great Recession were justified in case they actually turned out to be true. Yet many of these messages were contradicted by the available evidence. Most often the messages involved reporting trends seen only at a minority of libraries as if these applied to the majority of libraries. That’s is essentially what the pronouncements listed above do.
A typical example of claims that contradict actual evidence appeared in the Online Computer Library Center (OCLC) report Perceptions of Libraries, 2010. Data in that report showed that 69% of Americans did not feel the value of libraries had increased during the recession. Nevertheless, the authors pretended that the 31% minority spoke for all Americans, concluding that:
Millions of Americans, across all age groups, indicated that the value of the library has increased during the recession.2
In our enthusiasm for supporting libraries we should be careful not to be dishonest.
But enough about information accuracy and balance. Let’s move on to some nitty-gritty data exploration! For this I want to look at certain trees in the library forest. The data we’ll be looking at are just for urban and county public library systems in the U.S. Specifically, the 44 libraries with operating expenditures of $30 million or more in 2007.3 The time period analyzed will be 2007 to 2011, that is, from just prior to the onset of the Great Recession to two years past its official end.
Statistically speaking, a forest-perspective can still compete with a tree-perspective even with a small group of subjects like this one. Here is a graph showing a forest-perspective for the 44 libraries:
Median collection expenditures for large U.S. urban libraries. Click to see larger graph.
You may recall that a statistical median is one of a family of summary (or aggregate) statistics that includes totals, means, ranges, percentages/proportions, standard deviations, and the like. Aggregate statistics are forest statistics. They describe a collective as a whole (forest) but tell us very little about its individual members (trees).
To understand subjects in a group we, of course, have to look at those cases in the data. Trellis charts are ideal for examining individual cases. A trellis chart—also known as a lattice chart, panel chart, or small multiples—is a set of statistical graphs that have been arranged in rows and columns. To save space the graphs’ axes are consolidated in the trellis chart’s margins. Vertical axes appear in the chart’s left margin and the horizontal axes in the bottom or top margin or both.
Take a look at the chart below which presents data from agricultural experiments done in Minnesota in the 1930’s. It happens that the data depicted there are famous because legendary statistician R. A. Fisher published them in his classic 1935 book, The Design of Experiments. Viewing the data in a trellis chart helped AT&T Bell Laboratories statistician William Cleveland discover an error in the original data that went undetected for decades. The story of this discovery both opens and concludes Cleveland’s 1993 book Visualizing Data.4
Trellis chart depicting 1930′s agricultural experiments data.
Source: www.trellischarts.com. Click to see larger image.
At the left side of the chart notice that a list of items (these are barley seed varieties) serves as labels for the vertical axes for three graphs in the top row. The list is repeated again, serving as axes labels for the graphs in the second row. On the bottom of the chart numbers (20 to 60) are repeated and form the horizontal scales for the two graphs in each column. The layout of a trellis chart provides more white space so that the eye can concentrate on the plotted data alone, in this case circles depicting experimental results for 1931 and 1932.
With multiple graphs arranged side by side a trellis chart makes it easy to compare how different cases (aka research subjects) compare on a single measure. The chart below shows more about how this works using library data:
Trellis chart example with library collection expenditures data. Click for larger image.
The chart presents collection expenditures as a percent of total operating expenditures from 2007 to 2011. The cases are selected libraries as labeled. Notice how easy it is to identify the line shapes—like the humped lines of Atlanta, Baltimore, Cuyahoga Co., and Hawaii. And the bird-shapes of Brooklyn and Hennepin Co. And the District of Columbia’s inverted bird. Trellis charts make it easy to find similarities among individual trends, such as the fairly flat lines for Baltimore Co., Broward Co., Cincinnati, Denver, and King Co. Nevertheless, the charts presented here are more about identifying distinct patterns in single graphs. Each graph tells a unique story about a given library’s changes in annual statistics.
Incidentally, the trellis charts to follow have been adapted slightly to accommodate cases with exceptionally high data values. Instead of appearing in alphabetical order with other libraries in the chart, graphs for cases with high values appear in the far right column as shown in this one-row example:
Row from trellis chart with high value graph shaded and in red.
Click for larger image.
Notice that the graph at the right is shaded with its vertical axis clearly labeled in red, whereas the vertical axes for the non-shaded/black-lettered graphs appear at the left margin of the chart row. In this post all shaded/red-lettered graphs have scaling different from the rest of the graphs in the chart. By using extended scaling just for libraries with high values, the scaling for the rest of the libraries can be left intact.6
With that explanation out of the way, let’s look for some stories about these 44 urban and county libraries beginning with total operating expenditures:
Total Operating Expenditures. Click charts for larger images. Click text links for interactive charts.
Take a moment to study the variety of patterns among the libraries in these charts. For instance, in chart #1 Brooklyn, Broward County, Cleveland, and Cuyahoga Co. all had expenditure levels that decreased significantly by 2011. Others like Denver, Hawaii, Hennepin Co., Houston, Multnomah Co., and Philadelphia had dips in 2010 (the Great Recession officially ended in June the prior year) followed by immediate increases in 2011. And others like Boston, Orange Co. CA, San Diego Co., and Tampa had their expenditures peak in 2009 and decrease afterwards.
Now look at collection expenditures in these next two charts. You can see, for instance, that these dropped precipitously over the 4-year span for Cleveland, Los Angeles, Miami, and Queens. For several libraries including Atlanta, Baltimore, and Columbus expenditures dipped in 2010 followed by increases in 2011. Note also other variations like the stair-step upward trend of Hennepin Co., Houston’s bridge-shaped trend, the 2009 expenditure peaks for King Co., Multnomah, San Diego Co., and Seattle in 2009, and Chicago’s intriguing sideways S-curve.
Collection Expenditures. Click charts for larger images. Click text links for interactive charts.
Again, with trellis charts the main idea is visually scanning the graphs to see what might catch your eye. Watch for unusual or unexpected patterns although mundane patterns might be important also. It all depends on what interests you and the measures being viewed.
Once you spot an interesting case you’ll need to dig a little deeper. The first thing to do is view the underlying data since data values are typically omitted from trellis charts. For instance, I gathered the data seen in the single graph below for New York:
Investigating a trend begins with gathering detailed data. Click for larger image.
The example trellis chart presented earlier showed collection expenditures as a percent of total operating expenditures. This same measure is presented in the next charts for all 44 libraries, including links to the interactive charts. Take a look to see if any trends pique your curiosity.
Percent Collection Expenditures . Click charts for larger images. Click text links for interactive charts.
Exploring related measures at the same time can also reveal things about a data pattern we’re investigating. For example, collection expenditure patterns are made clearer by seeing how decreases in these compare to total expenditures. And how collection expenditures as a percentage of total expenditures relate to changes in the other two measures. The charts below make these comparisons possible for the 4 libraries mentioned earlier—Cleveland, Los Angeles, Miami, and Queens:
Understanding collection expenditure trends via multiple measures. Chart #1, trends alone. Chart #2, data values visible. Click charts for larger images. Click text links for interactive charts.
The next step is analyzing the trends and comparing relevant figures, with a few calculations (like percentage change) thrown in. Cleveland’s total expenditures fell continuously from 2007 to 2011, with a 20% cumulative decrease. The library’s collection expenditures decreased at nearly twice that rate (39%). As a percent of total expenditures collection expenditures fell from 20.4% to 15.6% over that period. Still, before and after the recession Cleveland outspent the other three libraries on collections.
From 2007 to 2010 Los Angeles’ total expenditures increased by 6% to $137.5 million, then dropped by 24% to $113.1 million. Over the 4-year span this amounted to a 13% increase. For that same period Los Angeles’ collection expenditures decreased by 45%. By 2010 Miami’s total expenditures had steadily increased by 38% to $81.8 million. However, in 2011 its expenditures fell to $66.7 million, a 17% drop from 2010 level but an increase of 13% over the 2007 level. Miami’s collection expenditures decreased by 78% over from 2007 to 2011, from $7.4 million to $1.6 million.
Total expenditures for Queens increased by 17% from 2007 to 2009, the year the Great Recession ended. Then by 2011 these expenditures dropped to just below 2007 levels, a 2% cumulative loss over the 4 years and a 19% loss from the 2009 level. From 2007 to 2011, though, Queens collection expenditures declined by 63% or $7.3 million.
Talk about data telling stories! Three of the 4 libraries had percent of total expenditures spent on collections decrease to below 6% in the aftermath of the recession. To investigate these figures futher we would need to obtain more information from the libraries.
As you can see, trellis charts are excellent tools for traipsing through a data forest, chart by chart and tree by tree. Obviously this phase takes time, diligence, and curiosity. Just 44 libraries and 5 years’ worth of a half-dozen measures produces a lot of data! But the effort expended can produce quite worthwhile results.
If your curious about other interesting trends, the next two sets of charts show visits and circulation for the 44 urban and county public libraries. Looking quickly, I didn’t see much along the lines of unprecedented demand for services. Take a gander yourself and see if any stories emerge. I hope there isn’t bad news hiding there. (Knock on wood.)
Visits. Click charts for larger images. Click text links for interactive charts.
Circulation. Click charts for larger images. Click text links for interactive charts.
1 The 2007 through 2010 expenditure data presented here have been adjusted for inflation. The data have been re-expressed as constant 2011 dollars using the GDP Deflator method specified in IMLS Public Libraries in the United States Survey: Fiscal Year 2010 (p. 45). For example, because the cumulative inflation rate from 2007 to 2011 was 6.7%, if a library’s total 2007 expenditures were $30 million in 2007, then for this analysis that 2007 figure was adjusted to $32 million.
Standardizing the dollar values across the 4-year period studied is the only way to get an accurate assessment of actual expenditure changes. A 2% expenditure increase in a year with 2% annual inflation is really no expenditure increase. Conversely, a 2% expenditure decrease in a year with 2% annual inflation is actually a 4% expenditure decrease.
2 Online Computer Library Center, Perceptions of Libraries, 2010: Context and Community, p. 44.
3 In any data analysis where you have to create categories, you end up drawing lines somewhere. To define large urban libraries I drew the line at $30 million total operating expenditures. Then, I based this on inflation adjusted figures as described in footnote #1. So any library with unadjusted total operating expenditures equal to or exceeding $28.2 million in 2007 was included.
4 See anything unusual in the chart? (Hint: Look at the chart labeled Morris.) The complete story about this discovery can be found here. Page down to the heading Barley Yield vs. Variety and Year Given Site. See also William S. Cleveland’s book, Visualizing Data, pp. 4-5, 328-340.
5 Using ordinary graphical tools statistician Howard Wainer discovered a big mistake in data that were 400+ years old! His discovery is described in his 2005 book, Graphic Discovery: A Trout in the Milk and Other Visual Adventures. Wainer uncovered anomalies in data appearing in an article published in 1710 by Queen Anne’s physician, John Arbuthnot. The original data were registered christenings and burials collected in England from 1620 to 1720 at the orders of Oliver Cromwell. See Wainer, H. Graphic Discovery, 2005, pp.1-4.
6 The chart below illustrates how a larger scale affects the shapes of a trend line. The scale in the left graph ranges from $25M to $100M, while the scale of the right graph ranges from $25M to $200M. Because the left graph scaling is more spacious (smaller scaling), its trend line angles are more accentuated.
Click for larger image.