Saturday, January 5, 2013

You want flying cars? I'll give you flying cars

As mentioned before, I'm a fan of David Graeber's recent essay, "Of Flying Cars and the Declining Rate of Profit" but I really dislike the title.  Flying cars have become the go-to cliche when discussing underperforming technological progress. On top of that, they have a slightly goofy quality and often come with the at least the implication that no one serious ever actually believed this stuff.


The last part is especially unfortunate because for most of the Twentieth Century, personal aviation was seen as something very close that was going to be very big. Exactly which technology (flying cars, personal planes, and, in the post-war era, jet-packs) would come to dominate was an open question, but serious people believed that flying would become very much like driving for things like commuting and they were willing to back up that belief with money and research.

I n 1933 the U. S. government spent half a million dollars to produce a ‘poor man’s airplane through the efforts of Eugene Vidal, promising a 2-3 seat, all metal aircraft costing $700 (the approximate price of a nice car and considerably less than any aircraft). While this effort was not embraced by the aircraft manufacturers of the time and portrayed as “an all mental aircraft”, the idea was enthusiastically greeted by the public. A direct result of this research was the Erco Ercoupe, which achieved new levels of ease of use, along with a spin-proof, safe stalling, smallfield capable, inexpensive aircraft. T.P. Wright, the Administrator of Civil Aeronautics, wrote an extensive review of NACA small aircraft efforts to “meet the needs of the family”. “When the market for all other types of planes is grouped it is apparent that what may be termed a really large industry, and one having an important effect on national economy, will not be provided. Of course the market for military aircraft will for a long time represent possibly the most important field in aircraft development and manufacture. However, even considering this with the others it can readily be seen that, developed to an adequate extent, the personal aircraft can easily become the most important factor in the aircraft industry. Used both for business and pleasure it is here only that an almost limitless potential market is available.”
Vidal was so committed that he even used his young son to demonstrate (at least briefly) how safe and easy flying these aircraft could be.



Gore Vidal, born Eugene Luther Gore Vidal Jr. on Oct. 3, 1925, in West Point, N.Y., was the only child of First Lieutenant Eugene Luther Vidal and Nina Gore, a socialite. His father was the first aeronautics instructor of the U.S. Military Academy and later the director of the Commerce Department's Bureau of Air Commerce during the Roosevelt Administration. Vidal's father had so much faith in the Hammond flivver-type plane that he sent 10-year-old Gore aloft to fly it. Vidal is pictured at the controls before takeoff. 
The flying car starts looking a bit less goofy in this context. Personal aircraft were soon supposed to be common. Neighborhoods would have their own airstrips. The idea of an airplane that was easily transportable and could double as a family automobile had obvious appeal.

By the Forties, these ideas had even reached the prototype stage


Taylor's design of a roadable aircraft dates back to 1946 [first flight 1949]. During a trip to Delaware, he met inventor Robert E. Fulton, Jr., who had designed an earlier roadable airplane, the Airphibian. Taylor recognized that the detachable wings of Fulton’s design would be better replaced by folding wings. His prototype Aerocar utilized folding wings that allowed the road vehicle to be converted into flight mode in five minutes by one person. When the rear license plate was flipped up, the operator could connect the propeller shaft and attach a pusher propeller. The same engine drives the front wheels through a three-speed manual transmission. When operated as an aircraft, the road transmission is simply left in neutral (though backing up during taxiing is possible by using reverse gear.) On the road, the wings and tail unit were designed to be towed behind the vehicle. Aerocars can drive up to 60 miles per hour and have a top airspeed of 110 miles per hour.
Mid-century Americans had every reason to have high expectations for this type technology. The past fifty years had seen far cruder prototypes of technology such as the car, airplane and helicopter develop into impressive and commercially viable machines. With the Depression and the war out of the way, there was every reason to believe that the turn-around time from early working model to full production would only get faster. If they could build one jet pack today, surely they could have the bugs worked out in a year or two.




That's a Bell Rocket Belt, in case you're curious.

We could argue about exactly why personal aviation never grew beyond the small niche it has occupied for the past few decades, but there's no question that a time traveler from fifty years ago would be surprised at our lack of progress in this area.

Nor do we have a lot of progress to report in the rest of transportation. I'm still not sure how to explain why we actually regressed in terms of transatlantic travel speeds from what we were doing thirty years ago.

Friday, January 4, 2013

Of outhouses and automobiles

Both Megan McArdle and Matt Yglesias have interesting posts about how important network effects can be to the adoption of new pieces of technology (Megan is talking about indoor plumbing, Matt about automobiles).  An except

Saying that people are choosing the a cell phone over an outhouse is not the same as saying they’re choosing a cell phone over an indoor toilet. Maybe that’s the choice they’d make, if they had it—I don’t know! But as Kelly’s own account acknowledges, they don’t actually have that choice, and certainly not at anything like the same cost.

Indoor plumbing requires either electricity to pump the water, and a nearby well to pump it from, or a connection to a public system with enough pressure to force the water high enough to flush your toilet. That’s a lot of power, not a trickle charge off of a small solar cell; I believe my great grandparents used a gasoline generator when they installed indoor plumbing in the mid-thirties. Gasoline generators are fairly expensive, as is the gasoline to run them, and I gather that they were only able to do it because their newly married son (my grandfather) saved up to help pay the installation cost, and then paid them rent that covered the cost of the fuel. Most farmers, I am told, waited until rural electrification brought them grid power.
 
Mark also pointed out just how important these elements of infrastructure were in transforming American society.  It's humbling to think about just how much effort was required to actually do all of these things (and concerning that infrastructure moves much slower today). 

However, I am hoping that the shift to an information based economy will have other benefits.  In some sense, there is a possibility that information, stored as pixels, could be something of real value (think of books or television programs) yet require very little resources to create.  In that sense maybe we could end up being happier (overall) while using less resources.

That being said, I have also used an outhouse and have absolutely no interest in giving up my indoor plumbing.  I am not even all that happy camping, unless there is a rest area in the middle of the campground with flush toilets (essential) and showers (highly desierable). 

Thursday, January 3, 2013

"Back when 50 miles was a long way"

Over at Statistical Modeling, Causal Inference, and Social Science, Phil picks up on the then-and-now theme and points us to this post from Michael Graham Richard with historic maps showing travel time from New York City in 1800, 1830, 1857, and 1930.



The maps are worth spending some time with (as is the comment section on Phil's post). They're also a nice segue to this observation from David Graeber's excellent essay:
Toffler’s use of acceleration was particularly unfortunate. For most of human history, the top speed at which human beings could travel had been around 25 miles per hour. By 1900 it had increased to 100 miles per hour, and for the next seventy years it did seem to be increasing exponentially. By the time Toffler was writing, in 1970, the record for the fastest speed at which any human had traveled stood at roughly 25,000 mph, achieved by the crew of Apollo 10 in 1969, just one year before. At such an exponential rate, it must have seemed reasonable to assume that within a matter of decades, humanity would be exploring other solar systems. 
Since 1970, no further increase has occurred. The record for the fastest a human has ever traveled remains with the crew of Apollo 10. True, the commercial airliner Concorde, which first flew in 1969, reached a maximum speed of 1,400 mph. And the Soviet Tupolev Tu-144, which flew first, reached an even faster speed of 1,553 mph. But those speeds not only have failed to increase; they have decreased since the Tupolev Tu-144 was cancelled and the Concorde was abandoned.

Wednesday, January 2, 2013

Miles instead of years

Phil has a great follow-up to Mark's when 50 years was a long time ago post.

Enjoy.

P.S. I was personally struck by just how isolated the Puget Sound area really was in 1857; 6 weeks is an amazingly long trip to still be in the same country.

P.P.S. I should look at the scheduled posts before saying anything.  Suffice it to say, a post with a lot more actual thinking is forthcoming and, having run across it in the archives, it is worth the wait

Megan McArdle's collectivist libertarianism

McArdle has come in, quite rightly, for a great deal of criticism following her recent post suggesting:
I’d also like us to encourage people to gang rush shooters, rather than following their instincts to hide; if we drilled it into young people that the correct thing to do is for everyone to instantly run at the guy with the gun, these sorts of mass shootings would be less deadly, because even a guy with a very powerful weapon can be brought down by 8-12 unarmed bodies piling on him at once.
In terms of tactics, simply rushing a gunman whose weapons may be fully automatic is an extraordinarily bad idea, truly a last resort. It looks good in the movies but in real life, every aspect of the maneuver -- range, position, response time -- plays to the shooter's advantage. This is pretty much the situation that assault weapons were designed for.

In terms of implementation, it is arguably even less practical. As an old history professor of mine (who happened to be ex-military) explained, when someone shoots at you, the overwhelming instinct is to run away which is why so much military culture is designed to condition soldiers to reflexively follow orders (and why officers sometimes point their sidearms at their own troops).

Jonathan Chait pointed out that even in the familiar and controlled setting of a football practice, it takes considerable training to get kids to rush toward large, threatening opponents without hesitating or flinching. The idea of getting typical elementary school children to instinctively swarm an armed gunman is so absurd that Chait concluded:
Unless I am missing a very subtle parody of libertarianism, McArdle’s plan to teach children to launch banzai charges against mass murderers is the single worst solution to any problem I have ever seen offered in a major publication.
That's the one part I disagree with, not about it being the worst solution but about it being libertarian. McArdle is suggesting that we institute what can only be a massive government program to indoctrinate kids to put aside personal choice and individual initiative and instead automatically take collective action to serve the interests of the group. I honestly can't think of a recent proposal more at odds with libertarian principles.

This last point has no real significance in the gun control debate. McArdle's idea was next to impossible to implement and was unlikely to work even if you could get it in place. The fact that it contradicted her stated core values has no bearing on the question of guns and safety.

It does matter, however, when we consider the larger and, in the long run more important, question of how to have a discussion (more important than keeping our children safe? Yes. We have to be able to intelligently discuss the problem before we can hope to address it). A great deal of our discourse on almost every major issue is staked out by nominal libertarians like McArdle.

Libertarianism is often treated as the respectable and intellectually coherent branch of conservative thought, particularly when compared with say. social conservatives or nativists, but if you start with the same axioms these groups hold about the validity and interpretation of certain sacred texts or about cultural identity respectively, then most of the positions held by social conservatives and nativists are at least coherent. By comparison, much. perhaps most, of what we hear from leading libertarians like McArdle is completely inconsistent with the defining assumptions of libertarianism.

With a few exceptions, most of the nominal libertarians seem to take a curiously pro-authority stance, particularly when that authority preserves the social order. Even when the authority is governmental, actions that greatly reduce aggregate liberty (the war on drugs, extensions of copyrights and patents), are objected to less strenuously than are policies that arguably increase aggregate liberty such as civil rights laws.

Update: You can see Megan's response to this post in the comment section.

When Patents attack

Kevin Drum has an interesting story about a software patent case:

This hits home for me in two ways. First, the alleged patents date from 1996, and I was personally involved in a project to put scanners on networks starting around 1994. It was cleverly called NetScan, and it eventually failed for a variety of reasons, but by 1996 we had an actual box on the market that allowed you to connect a scanner and program it to send documents to your internal email account. I have no doubt that the patent trolls in this case would argue that the technology we used was subtly different from theirs (we emailed TIFF files, for example, while their patent covers PDFs), but that's almost certainly legalistic nonsense. You connected a scanner to our box, entered a bunch of data identifying users, and then you could scan documents and have them automatically emailed to your desktop. We didn't even bother patenting it because the idea was pretty obvious.
I think that this makes it pretty clear how silly a lot of modern patent law has become.  There is not really any innovation being protected here and, instead, we have a lot of lawyers becoming rich because somebody decided to take out a patent on what people were already doing. 

This makes me extremely skeptical that patents are a direct correlate with innovation, unless you sub-group them very carefully.   And it is highly disturbing to see small businesses (which don't have deep pockets for legal fees) being increasingly targeted by patent lawyers.  There are already a lot of barriers to being a small business.  A catalogue of patents for simple things (like scanning a document to email) would be cumbersome and trying to be compliant with it would be the most onerous set of regulations I can imagine.

Monday, December 31, 2012

Bad grading idea

Via Tyler Cowen:
 I will submit your papers (blind) to external referees as well as myself for assessment, an A grade will be limited to those papers, and only those papers, that are recommended for acceptance or conditional acceptance, a B grade will be assigned to those papers that receive a recommendation of revise and resubmit, and a C grade will be assigned to those papers that are rejected by the external referees and myself.
 
I would be quite annoyed to discover that I was putting in the hours to evalaute a paper only to discover that I was doing a professor's job of grading said paper.  Furthermore, it seems that the editor is also the professor for the course.  I would be reluctant to evaluate a student or peer at tmy institution.  The less distance, the more I would be reluctant to do so.  The professor in queestion is willing to blind the papers for the external reviewers, who can not possibly be as potentially biased as a professor with their own students. 

I am also wondering about the standards of a journal in which revise and resubmit is a B grade.  There cannot be many A's.  I have (once) had a paper accepted without revisions but it was definitely not the first time it was ever sent to a journal.  The idea that a paper done in a single semester course (in parallel with other classes) would be a paper so high quality that it was accepted without revisions less than 4 months of work would be incredible in Epidemiology. 

Sunday, December 30, 2012

Back when fifty years was a long time ago




I've noticed over the past year or two that people ranging  from Neal Stephenson  to Paul Krugman have been increasingly open about the possibility that technological progress been under-performing lately (Tyler Cowen has also been making similar points for a while). David Graeber does perhaps the bst job summing up the position (though I could do without the title).

The case that recent progress has been anemic is often backed with comparisons to the advances of the late Nineteenth and early Twentieth Centuries (for example).  There are all sorts of technological and economic metrics that show the extent of these advances but you can also get some interesting insights looking at the way pop culture portrayed these changes.

Though much has been written pop culture attitudes toward technological change, almost all focus on forward-looking attitudes (what people thought the future would be like). This is problematic since science fiction authors routinely mix the serious with the fanciful, satiric and even the deliberately absurd. You may well get a better read by looking at how people in the middle of the Twentieth Century looked at their own recent progress.



In the middle of the century, particularly in the Forties, there was a great fascination with the Gay Nineties. It was a period in living memory and yet in many ways it seemed incredibly distant, socially, politically, economically, artistically and most of all, technologically. In 1945, much, if not most day-to-day life depended on devices and media that were either relatively new in 1890 or were yet to be invented.  Even relatively old tech like newspapers were radically different, employing advances in printing and photography and filled with Twentieth Century innovations like comic strips.

The Nineties genre was built around the audiences' self-awareness of how rapidly their world had changed and was changing. The world of these films was pleasantly alien, separated from the viewers by cataclysmic changes.

The comparison to Mad Men is useful. We have seen an uptick in interest in the world of fifty years ago but it's much smaller than the mid-Twentieth Century fascination with the Nineties and, more importantly, shows like Mad Men, Pan Am and the Playboy Club focused almost entirely on social mores. None of them had the sense of travelling to an alien place that you often get from Gay Nineties stories.

There was even a subgenre built around that idea, travelling literally or figuratively to the world of the Nineties. Literal travel could be via magic or even less convincing devices.


(technically 1961 is a little late for this discussion, but you get the idea)

Figurative travel involved going to towns that had for some reason abandoned the Twentieth Century. Here's a representative 1946 example from Golden Age artist Klaus Nordling:








There are numerous other comics examples from the Forties, including this from one of the true geniuses of the medium, Jack Cole.












More on Glaeser and Houston

From the comment section to my recent post on Edward Glaeser (from a reader who was NOT happy with my piece), here's a quote from Glaeser that does put Houston where it belongs:
If our Houston family's income is lower, however, its housing costs are much lower. In 2006, residents of Harris County, the 4-million-person area that includes Houston, told the census that the average owner-occupied housing unit was worth $126,000. Residents valued about 80% of the homes in the county at less than $200,000. The National Association of Realtors gives $150,000 as the median price of recent Houston home sales; though NAR figures don't always accurately reflect average home prices, they do capture the prices of newer, often higher-quality, housing.
Just to review, I had criticized Glaeser for this quote:
Why is housing supply so generous in Georgia and Texas? It isn’t land. Harris County, Tex., which surrounds Houston, has a higher population density than Westchester County, N.Y.
So should we write off the "surrounds" as a bad choice of words and move on to another topic? Not quite yet. The trouble is that the placement of Houston doesn't just shift; it shifts in a way that's necessary for Glaeser's argument to work. If Houston weren't in Harris then the Westchester comparison would make sense. Here are the population densities (all numbers courtesy of Wikipedia)

Harris             2,367/sq mi
Westchester    2,193/sq mi

But Harris does include Houston. None of the counties that contain parts of NYC have a density lower than Harris (not even close). Of course, the county to county comparisons are problematic, but we get the same results from the much cleaner city-to-city comparison.

Houston              3,623/sq mi
New York City   27,012.5/sq mi

We could go back and forth on the best way to slice this data, but this is a big difference to get around. This doesn't mean that population density is driving the difference in housing between New York and Houston or regulation isn't the main driver here.

But the Harris/Westchester example Glaeser used to prove his point was badly chosen and it's worrisome that neither he, the New York Times or the vast majority of the blogosphere picked up on that.


Saturday, December 29, 2012

Glaeser... Glaeser... Where have I heard that name before?

Joseph's last post has got me thinking that it might be a good time for a quick Edward Glaeser retrospective.

Glaeser is, unquestionably, a smart guy with a lot of interesting ideas. Unfortunately, those ideas come with a heavy dose of confirmation bias, a bias made worse by a strong tendency to see the world through a conservative/libertarian filter, a provincial attitude toward much of the country and a less than diligent approach to data. The result is often some truly bizarre bits of punditry.

The provincialism and cavalier approach are notably on display in this piece of analysis involving Houston, a city Glaeser has written about extensively.
Why is housing supply so generous in Georgia and Texas? It isn’t land. Harris County, Tex., which surrounds Houston, has a higher population density than Westchester County, N.Y.
The trouble is Houston is IN Harris County (technically, the town does spill over into a couple of other counties -- Texas counties are on the small side -- but it's mainly Harris).




Keep in mind that Glaeser is one of the leading authorities on cities and Houston is one of his favorite examples.

[Update: Glaeser has correctly placed Houston is Harris County in the past, though the Harris/Westchester comparison still raises questions.]

Glaeser's flawed example was part of a larger argument that "Red State growth is that Republican states have grown more quickly because building is easier in those states, primarily because of housing regulations. Republican states are less prone to restrict construction than places like California and Massachusetts, and as a result, high-quality housing is much cheaper."

Like so much of Glaeser, it's an interesting idea with some important implications but as presented it doesn't really fit the data.

This confirmation bias can lead to some other truly strange examples:
But there was a crucial difference between Seattle and Detroit. Unlike Ford and General Motors, Boeing employed highly educated workers. Almost since its inception, Seattle has been committed to education and has benefited from the University of Washington, which is based there. Skills are the source of Seattle’s strength.
The University of Michigan is essentially in a suburb of Detroit. UM and UW are both major schools with similar standings. Washington is better in some areas, Michigan is better in others, but overall they are remarkably close. When you add in Wayne State (another fine school), the argument that Seattle is doing better than Detroit because of the respective quality of their universities is, well, strange.

Glaeser's confirmation bias has led him to make a number of other easily refuted arguments. His predictions about the auto bailout aren't looking good. Joseph pointed out numerous problems with his statements about food stamps. Dominik LukeÅ¡ demolished his school/restaurant analogy. His claims about Spain's meltdown are simply factually wrong.

To make matters worse, Glaeser doesn't seem to show much interest in engaging his critics. As far as I know, none of these points have ever been addressed.



Friday, December 28, 2012

Disability and work

Via Brad Delong we have this quote from Eschaton:

It's an economist way to think about things, that someone being in the labor force means they're choosing the "work option." But in recession the options for some are no work and no money (otherwise known as "homelessness") or managing to qualify for disability (average monthly payment about $1100, max benefit about $2500). If you have some form of disability, you might be able to work if you have a job and employer that can accommodate you, but lose that job and you're probably going to be out of luck.

This isn't really mysterious stuff. Someone is 61, has a moderate disability, and loses his/her job. There is no work option.
This was in response to an article by Edward Glaeser puzzling over why the social security disability roles are suddenly rising, including such gems as

Ultimately, the best recipe for fighting poverty is investment in human capital. This starts with improving our education system, an undertaking that should include experiments with digital learning, incentives for attracting good teachers and retooling community colleges so they provide marketable skills to less-advantaged Americans.


and
The steady rise in disability claims presents something of a puzzle. Medicine has improved substantially. Far fewer of us labor in dangerous industrial jobs like the ones that originally motivated disability insurance. The rate of deaths due to injuries has plummeted. Behavior that can cause disability, such as alcohol use and smoking, has declined substantially. American age-adjusted mortality rates are far lower than in the past.
Has Professor Glaeser noted tuition costs lately?  Or looked at the consequences of defaulting on student loans?  The opportunity cost for a semi-disabled worker to go back to school, go wildly into debt and then risk having social security garnished to pay wages is very high. 

The real issue is unemployment.  That is the root source of declining skills and it is reasonable that firms may be less likely to hire disabled workers in a recession.  Add in the lack of mobility that we have added with the housing crash and this is not at all mysterious why people might have trouble breaking back into the work force once they are delayed. 

As for reduced mortality, sometimes that goes the other direction.  Saving a person from a heart attack (who would previously have died) may result in a person with lower cardiac function and with less endurance than before.  In a full employment scenario they can fight to stay in the workforce because there is a shortage of good people.  But in a massive recession they can no longer compete and disability is actually a correct description of why they cannot compete. 


Thinking about the math of board games over at You Do the Math




Thursday, December 27, 2012

I'll be talking about the future in the future

And I will definitely be discussing this article by David Graeber and this one by Robert J. Gordon. I have with both (particularly the Gordon piece) but they are still good, thought-provoking and important. Read'em both and we'll talk about it later.

A poverty comment

There were wo articles that led to me agreeing with Matt Yglesias about refocusing on cash transfers and wporrying less about how the money is spent.  One, was an expose on how the state of Georgia tries to keep people from receiving benefits.  Now it is fair pool to decide that, as a state or a society, that you don't want to give these benefits.  But doesn't it make sense to make that decision transparently instead of slowing adding in extra steps?

The other one was a link I found on Felix Salmon's webste called "Stop subsizing obesity".  What made this article surreal was that we did not get a discussion of ways to change agricultural subsidies to make high fructose corn syrup a less prevalent addition.  No, what we go was an attack on food stamps:
This could happen in two ways: first, remove the subsidy for sugar-sweetened beverages, since no one without a share in the profits can argue that the substance plays a constructive role in any diet. “There’s no rationale for continuing to subsidize them through SNAP benefits,” says Ludwig, “with the level of science we have linking their consumption to obesity, diabetes and heart disease.” New York City proposed a pilot program that would do precisely this back in 2011; it was rejected by the Department of Agriculture (USDA) as “too complex.”
 
Now, of all the targets they could go after, soda is the one that I am the most sympathetic to.  I have bene trying (with mixed success) to radically reduce my own consumption of the substance.  But look at the sorts of ideas that come out next:


Simultaneously, make it easier to buy real food; several cities, including New York, have programs that double the value of food stamps when used for purchases at farmers markets. The next step is to similarly increase the spending power of food stamps when they’re used to buy fruits, vegetables, legumes and whole grains, not just in farmers markets but in supermarkets – indeed, everywhere people buy food.
 
Can we say the word "arbitrage opportunity"?  Maybe it would be inefficient, but look at how much more complex you are making a very basic program in order to reach a social goal.  And why are we targeting it at food stamp recipients?  If this is a worthwhile way to combat obesity, why not use a vice tax (which is an approach I can at least conceptually support).

So these types of issues are what are making me think maybe we should be much more basic in our approach to charity. 

The difficulties in talking about TV viewership.

In response to this post on television's surprising longevity, Andrew Gelman pointed out that ratings really have plummeted:
[T]he other day I happened to notice a feature in the newspaper giving the ratings of the top TV shows, and . . . I was stunned (although, in retrospect, maybe I shouldn't've been) by how low they were. Back when I was a kid there was a column in the newspaper giving the TV ratings every week, and I remember lots of prime-time shows getting ratings in the 20's. Nowadays a top show can have a rating of less than 5.
Undoubtedly, there has been a big drop here (as you would expect given that broadcast television used to have an effective monopoly over home entertainment), but has the drop been as big as it looks? There are a few mitigating factors, particularly if we think about total viewership for each episode (or even each minute) of a show and the economics of non-rival goods:

1. 52 weeks a year
It took years for the networks to catch on to the potential of the rerun. You'll see this credited to the practice  of broadcasting live, but the timelines don't match up. Long seasons continued until well into the Sixties and summer replacement shows into the Seventies. With the advent of reruns, the big three networks started selling the same shows twice whereas before the viewers for the first time an episode aired was often all the viewers it would ever have. Should we be talking about the number of people who watched a particular airing or should we consider the total number of people who saw an episode over all its airings?


2. The big three... four... five... five and a half...
Speaking of the big three, when we talk about declining ratings, we need to take into account that the network pie is now sliced more ways with the addition of Fox, CW, Ion, MyNetwork and possibly one or two I'm forgetting.


3. But if you had cable you could be watching NCIS and the Big Bang Theory
A great deal of cable programming is recycled network programming. If we count viewership as the total number of times a program is viewed (a defensible if not ideal metric), you could actually argue that the number is trending up for shows produced for and originally shown on the networks.


4. When Netflix is actually working...
Much has been made of on-line providers as a threat to the networks, but much of their business model current relies streaming old network shows. This adds to our total views tally. (Attempts at moving away from this recycling model are, at best, preceding slowly.)


5.  I'm waiting for the Blu-ray
Finally, the viewership and revenue from network shows has been significantly enhanced by DVDs and Blu-rays


I don't want to make too much of this. Network television does face real challenges, cable has become a major source of programming (including personal favorites like Justified, Burn Notice and the Closer), and web series are starting to show considerable promise. The standard twilight-of-the-networks narrative may turn out to be right this time. I'm just saying that, given resilience if the institutions and the complexities of thinking about non-rival goods, I'd be careful about embracing any narrative too quickly.