Harold Miller has posted some graphical illustrations of his recent observations about job growth in the Pittsburgh region - or the lack thereof.
As JP observes in a comment on Harold's post, the data illustrate two phenomena which may be independent of one another: Pittsburgh's trend line lags the national trend by about a year, more or less. And Pittsburgh's growth rate overall remains significantly below the national average.
2 comments:
If I weren't so busy doing other things, I'd try and get the data and do some better visualizations. I really don't think that bar charts are the best kind of visualization, because they imply a lot of independence between the groups of bars, as if each month/year/3-year-period is independent of its neighbors.
The plot I would like to see would plot the monthly data going back 15-20 years, as curves -- reasonably smoothed to get rid of the noise that's so apparent in the month-to-month plots.
Then I'd like to cross-correlate the two curves (pgh vs national) to see what offset gives the best correlation between the two.
It would be interesting to do the same thing for other cities as well.
Looking at monthly data tends to obscure the trends rather than reveal them. There really isn't a consistent lag in Pittsburgh's job growth compared to the nation, other than in the recent recession. It's just a shortfall, which varies in amount from year to year, and which has gotten worse in the past few years. See the expanded chart at http://pittsburghfuture.blogspot.com/2007/05/visualizing-lack-of-job-growth.html
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