Posts

I couldn’t stop thinking about the possibilities that might be opened by a new Central Branch of the Howard County Library System, so I’m taking the unprecedented step of posting twice in one day. In my last post I proposed building a new Central Branch facility that included at least a dedicated co-working space and business resource center, and possibly having it also host the Innovation Catalyst program run by the Howard County Economic Development Authority in the same building, just as the Miller Branch currently hosts the Howard County Historical Society. ...

Unfortunately I won’t be able to attend the Evening in the Stacks fundraiser at the Miller Branch of the Howard County Library System. However that won’t stop me from doing a library-themed blog post to mark the occasion: Recently the Howard County Times published an article highlighting the HiTech program at the Savage Branch. To quote from the library’s web site, HiTech is a “new digital media lab for teens centering on science, technology, engineering and math.” It’s part and parcel of the library’s expanding role as an educational resource for Howard County residents. ...

Over at Columbia Compass Bill Santos has written a great post that brought into focus some of my thoughts around the proposed Inner Arbor project for Symphony Woods. I really like what I’ve heard and seen of the project and I hope it comes to fruition. But. . . I live in Ellicott City, not in Columbia, and when Ian Kennedy asked people to sign a petition in support of the project I was at first hesitant to do so. After all, I’m not a Columbia property owner, I don’t vote for the Columbia Association board of directors, and whatever money CA chooses to spend in support of the Inner Arbor project is not going to come out of my pocket. Should I just stay out of the controversy and leave Columbia-related matters to the “real Columbians”? ...

For the most part I’ve stayed out of the debate over the “Inner Arbor” plan proposed for consideration by the Columbia Association Board of Directors. For the record, I think the idea of having an everyday “there there” in Symphony Woods (i.e., not just Merriweather Post Pavilion) is a good idea; I especially like the idea of building a new Central Branch library as part of an overall Symphony Woods cultural complex. Bottom line: I like the proposal, have signed the petition to support it, and encourage others to do so as well. ...

I’m back to posting weekend recommendations, but this time it’s for listening instead of reading. One nice benefit of Spotify and similar services is that you can go back and listen to all those albums you never got around to buying, or sample new music you don‘t yet want to buy—or, if you’re truly a child of the Internet, you may never buy at all but simply listen via audio streams or YouTube.1 ...

In part 4 of this series I discussed the general problem of estimating growth rates for periods less than a year, and using Howard County’s population in the 21st century as an example calculated estimated monthly, week, daily, and even hourly growth rates for the county based on the Census population figures for 2000 and 2010. The problem with those calculations is that it’s hard to get a sense for the relative magnitude of the growth rates. For example, how much different is a growth rate of 0.12256% per month from a growth rate of 1.4807% per year? It would be nice to express the growth rates according to a common time period, just as (for example) we use “miles per hour” to refer to the speed of our cars even when we’re just driving 2 minutes to the grocery. ...

In part 3 of this series I recapped the method derived in part 2 for estimating growth rates (using Howard County’s population in the 21st century as an example) and discussed how to use such estimates to project growth in future years. Now let’s go back to a question I asked at the end of part 2: Can we calculate a more accurate estimate for the growth rate? We can begin exploring this question by going back to my original inaccurate estimate in part 1 and considering where I went wrong. To get that estimate I simply took the final population in 2010, divided it by the initial population in 2000, then divided that by 10 to get an annual growth rate (which I then converted to a percentage value). That initial estimate was too high: When I used that value to estimate the population in 2001, 2002, and so on, it produced a final population estimate for 2010 that was well in excess of the actual 2010 population. ...

In part 2 of this series I discussed a more correct approach to the problem of estimating growth rates, using Howard County’s population in the 21st century as an example. Given the population figures for the 2000 and 2010 censuses, we can estimate an annual growth rate as follows: Divide the final population in 2010 by the initial population in 2000. Take the 10th root of the result from step 1 to find the growth factor. (We use 10 because the period we’re considering is 10 years long.) Subtract 1 from the growth factor to find the growth rate. Multiply the growth rate by 100 to convert it into percentage form. Recall that you can take roots using a scientific calculator app for your smartphone, tablet, or PC, as described in the last post; you can also compute roots in a application like Microsoft Excel or Google Spreadsheets.1 ...

In my last post I introduced the problem of estimating growth rates, using Howard County’s population in the 21st century as an example. I took a simpleminded approach: Take the difference between the county’s population in 2010 and 2000. Divide that difference by the population in 2000 and multiply by 100 to get the percentage growth increase from 2000 to 2010. Divide that percentage by 10 to get an estimate of the population growth per year. As we saw in the last post, the simpleminded approach produces an incorrect answer: the estimated growth rate is too large. In this post I’ll show a more correct way to estimate the growth rate. As before, I’ll avoid mathematical notation and restrict myself to operations you can do on a calculator or in a program like Microsoft Excel or Google Spreadsheets. ...

[I’m interrupting my series of “weekend reading” posts to bring you an actual blog post.] Last week at work one of my tasks was estimating growth rates for a particular quantity (never mind exactly what). I found that doing this was not exactly trivial, as there are multiple ways to calculate growth rates, some of them more mathematically complicated than others. I think I now understand how this all works, and to test my understanding I’m going to try to explain it here. ...