B-C-A as Whipping Boy for Commentators

New London Airport in Hyde Park?
In the 1960s the Roskill commission was tasked with producing a report into the best location for the third London airport. Its findings were reached though cost-benefit analysis, assigning an arbitary economic value to the unquantifiable. The report famously valued a Norman church at just £50,000 (the cost of its fire insurance).

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Switching Between Relative and Absolute Cell References in Excel

OK, so I knew there must be an easier way to do this than to surgically insert dollar signs into formulas whenever you needed an absolute cell reference.

I thought maybe you could hold down the shift key as you pointed at a cell while constructing a formula and that would insert $row$col automatically. And maybe the control key would give you a dollar sign just on the row and the alt-key just on the column.

Well, I was right that there is a way, but not about what the way is. The following sitting right there in Excel help:

To switch between relative, absolute, and mixed references

1. Select the cell that contains the formula.


2. In the formula bar, select the reference that you want to change.


3. Press F4 to switch between the reference types.

Note, this also works during the initial input: just after you have clicked on a cell to get its reference into the formula, hit F4 to cycle through the three different dollar sign options (both, row only, column only, neither). Nice trick.

Systems Thinking and Modeling for Public Policy Analysis Workshop

(at University of Minnesota's Humphrey Institute of Public Affairs)

This workshop will consist of introductions to systems thinking, modeling and simulation. The emphasis will be on dynamic public policy problems, and problems that play out over time. Participants will...

Markov Models in International Relations

I spoke too soon in class today about not seeing an obvious application of Markov models to international relations. Stumbled across a set of papers by Philip A. Schrodt, applying a technique called "hidden Markov models" to international crises of various sorts at The Society for Political Methodology. Here's what the author had to say about a paper on recognizing patterns of events as "war" or "non-war":

Event data are one of the most widely used indicators in quantitative international relations research. To date, most of the models using event data have constructed numerical indicators based on the characteristics of the events measured in isolation and then aggregated. An alternative approach is to use quantitative pattern recognition techniques to compare an existing sequence of behaviors to a set of similar historical cases. This has much in common with human reasoning by historical analogy while providing the advantages of systematic and replicable analysis possible using machine-coded event data and statistical models. This chapter uses "hidden Markov models" -- a recently developed sequence- comparison technique widely used in computational speech recognition -- to measure similarities among international crises.

A Little Background on the Mortgage Crisis

Today's New York Times featured an "op-ed graphic" showing the relationship between mortgage type, loan-to-value ratios, and default rates.

The PDF of the handout distributed in class is here.

The IMF report from which a few of the diagrams were taken is "Assessing Risks to Global Financial Security."

Other Easy to Digest Background

This American Life did a nice piece called "The Giant Pool of Money" last year. Alex Blumberg and Adam Davidson (the guys who did this program) have a daily podcast and blog, Planet Money, about each day's news on the financial crisis.

The Obama administration has a website called "FinancialStability.gov" but as of this writing it still has a bit of a "coming soon" quality.

Difference Equations, Take Two

...is available at this link: http://courses.djjr.net/ppol225/diff-egns/Difference-Equations-2.pdf.

Practice problems are here.

Flow Charts in the Wild

One of the easiest tasks I've ever had is to find examples of "bad" flowcharts. Just google "flow chart" or "flowchart" and one will pop up.

I didn't have to look for this one -- it arrived in an email on our neighborhood listserv. Oakland City Council will apparently be considering a youth curfew ordinance this month (see council agenda packet).

Aside from the chart, the packet makes for an interesting read. It's an nice example of combining political, fiscal, and legal considerations to sell an idea (note that we don't expect this sort of document to look at pros and cons -- the authors are trying to get this passed). It's also provides some interesting examples of throwing numbers around in dubious ways (for example, why would 23% of all juvenile crimes happening during 25% of the hours of the day be an argument for a curfew?).