Towards a measure of welfare-relevant national output

Robert Barro says GDP overstates national income because it counts investment twice. 

Here is Scott Sumner explaining Barro’s point with an example:

Thus suppose Tesla builds a battery factory that costs $1 billion, which lasts for 20 years.  They hire workers and pay another $2 billion in wages over 20 years.  The batteries sell for a total of $3.3 billion, a profit margin of 10%.   In this example, $4.3 billion is added to GDP over the life of the factory—$1 investment and another $3.3 billion in consumer goods (batteries).   But there is actually only $3.3 billion worth of actual “goods” being produced; the $1 billion factory investment is an input.

As Scott Sumner points out, GDP isn’t meant to be a measure of national welfare, but of national output. This should always be kept in mind and should be pointed out whenever someone is using GDP per capita as a measure of welfare. But it’s clear that GDP, understood as national output, is really useful for many policy discussions.

That said, I was thinking about how to correct GDP to better measure that part of national output which is directly relevant to people’s wellbeing. And here’s what I would do: I would count all spending on consumption goods (private and public) as well as residential construction spending which is presently counted as „investment“. Following Barro’s critique I would not count spending on capital goods such as factories, machines, tools, and intellectual property which are only indirectly useful to consumers in so far as they help produce consumer goods in the future.

As for government consumption, I would suggest to apply a “waste correction” to take into account the fact that some of that consumption just isn’t useful to consumers. Spending billions of euros on a tunnel or an airport or a bridge which nobody has used yet or on a weapons system which (hopefully) will never be used, is to a large degree wasted money, although views will differ exactly how much of it is really wasted. At any rate, I think GDP should try to account for government waste.

So to sum up, I’d propose the following measure:

Welfare-relevant GDP
= Private consumption
+ Government consumption x (1 – waste ratio)
+ Investment in residential construction

Here’s what this would look like for Austria in 2018:


million euros, 2018
Private consumption199.459
Government consumption 74.295
      of which waste 14.859
Residential investment 17.232
Welfare-relevant GDP276.126
Conventional GDP386.063
Ratio: welfare-relevant 
/ conventionalGDP
71,5 %

In other words, conventional GDP overstates the supply of goods that are directly relevant for the welfare of households by almost 30%. I would like the welfare-relevant GDP measure to be used when comparing living-standard across countries or within countries across time. And I would like growth theory to focus on the growth of this measure.

(PS: What about exports and imports? Exports aren’t welfare-relevant for the home country, because those are goods consumed by foreigners. Imports are, of course, already included in measures of private and public spending measures. So there’s no need to add exports and subtract imports as done in conventional GDP.)

Confirmed: Raising tariffs is shooting yourself in the foot

As everybody knows from Econ 101, protective tariffs are harmful for the country that imposes them. A protective tariff is a tax on imports that is so high as to make all imports fall to zero.

But there is an argument why a low tariff may be better than no tariff at all. The reason is that a large country (large compared to its trading partners) faces an upward-sloping supply curve for its imports such that a fall in import demand lowers the world-market price of imported goods. Hence, part of the cost of the increased tariff would fall on the rest of the world due to lower export prices (a fall in the terms of trade) while the country that imposed the tariff might win overall.

Whatever the theoretical merits and demerits of this argument, recent experience with tariff increases in the US (aka Trump’s Trade War) provides powerful evidence against it.

In a newly released paper, Amiti, Redding and Weinstein show that the tariffs imposed last year by the Trump administration had two main effects:

1) US prices of imported goods rose one-for-one with increases in tariff rates.

2) Import demand decreased substantially with an estimated price elasticity of 6 (i.e. 6 percent lower imports for every 1 percent of higher tariffs).

As a consequence of these two results the paper estimates the welfare costs of the Trade War to be about 6.9 billion dollars. While that is not a huge number compared to the total size of the US economy, keep in mind that we’re only talking about a marginal change of the average tariffs from 1.5 to about 3.25 percent. And remember that the welfare costs rise with the square of the applied tariff rate. So should tariffs go up more in the future, the welfare costs will be much bigger.

I regard this as decisive evidence that the optimum tariff is indeed zero. Note that finding No. 1 implies that American consumers are paying the full cost of the tariff increase, with no terms-of-trade effect on the rest of the world. If even the largest economy in the world cannot improve their terms of trade by increasing tariffs, then smaller economies have no hope of doing so either. Raising tariffs is indeed shooting yourself in the foot.

Moreover, this paper is also a triumph for simple textbook economics. The results of Trump’s tariffs are exactly what one would expect from the kind of supply-and-demand model taught in Econ 101. As Tyler Cowen points out, the complete pass-through of tariffs to consumer prices also implies that monopoly power is not a big issue in these markets. It’s good to know that the much-maligned perfect competition partial equilibrium models still gets some important things right.

Good and bad monopolies: the case of Coca-Cola (or Red Bull)

In this series of short posts I give you my personal opinion (as it is at the moment) and my reasons for this opinion about how good or bad I believe different monopolies to be. I am planning six mini-case studies of monopolies. When I talk about a monopoly in this post I simply mean a firm that has some power over its price: it can choose a lower price and sell a bit more (but not super much more) or a higher price and sell a bit less (but not super much less). A firm with such a power will typically – see a previous post – choose a higher price and sell less than would be Pareto-efficient. And this way such a firm will typically make “abnormally” high profits. While all this is probably true in all six cases, I am, for various reasons, in fact not equally worried about every one of these. I want to discuss the following six “monopoly” cases: Coca-Cola (or Red Bull), Google, Facebook, Scientific Publishers such as Elsevier (possibly also publishers of €100 textbooks such as Pearson), the OPEC cartel of a set of oil producers, and pharmaceutical companies (such as Novartis). This one is about Coca-Cola, and applies equally to Red Bull.

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Wie sehr profitiert Österreich vom Außenhandel?

Paul Krugman zeigt uns wie man Handelsgewinne mit einer einfachen Formel berechnen kann und wendet sie auf den “Brexit” an. Seiner Berechnung zufolge würde ein harter Brexit ca. 2% vom britischen BIP kosten. 

Die Formel kommt aus einem mittlerweile zum Standard gewordenen Modell bilateraler Handelsströme von Johnathan Eaton und Samuel Kortum. Dieses Modell ist im Prinzip eine  Verallgemeinerung des „Ricardianischen Modells“, das wir alle im ersten Jahr VWL-Studium gelernt haben (wir erinnern uns: England tauscht Tuch gegen Wein aus Portugal,…), nur eben mit unendlich vielen Gütern und beliebig vielen Ländern. Die Formel setzt das Pro-Kopf-Realeinkommen einer Volkswirtschaft w in Beziehung zum Inlandsanteil seiner Gesamtausgaben („home share“) h:

w = a*h^(-b),

wobei die Konstante a die allgemeine Arbeitsproduktivität der Landes misst (je größer a, desto größer der „absolute Vorteil“ eines Landes) und der Parameter b die Streuung der Arbeitsproduktivität über die Länder hinweg bestimmt (je größer b desto stärker ausgeprägt sind die „komparativen Vorteile“ jedes Landes). Hier klicken, wer eine Herleitung sehen will. Eaton und Kortum und Krugman verwenden b=0,25 in ihren Berechnungen. Die Konstante a spielt für unsere Zwecke keine wesentlich Rolle.

Wie berechnet man den Inlandsanteil? Dazu müssen wir uns an die VGR-Identitäten erinnern. Das Bruttonationaleinkommen Y ist bekanntlich gleich den Gesamtausgaben eines Landes (Summe aus privatem und staatlichen Konsum und Investitionen) abzüglich der Netto-Exporte (Exporte X minus Importe M). Die Ausgaben auf inländische Güter erhält man indem man von den Gesamtausgaben die Importe abzieht oder wenn man vom Bruttonationaleinkommen die Brutto-Exporte abzieht. Das heißt wir können den Inlandsanteil wie folgt berechnen:

h = (Y-X)/(Y-X+M).

In einer geschlossenen Volkswirtschaft ist der Inlandsanteil gleich eins. Daraus folgt, dass das Pro-Kopf-Realeinkommen einer autarken Volkswirtschaft nur durch die allgemeinen Arbeitsproduktivität a bestimmt ist. Je offener die Volkswirtschaft, desto geringer der Inlandsanteil, desto größer sind die Handelsgewinne.

Nachstehende Grafik zeigt die Resultate meiner Berechnungen für die Österreich von 1995 bis 2017 (Daten von Eurostat). Warum 1995? Weil das das Jahr war, in dem Österreich zur EU beigetreten ist. Wie man sieht entfielen bei EU-Beitritt noch fast 2/3 der österreichischen Gesamtausgaben auf heimische Güter. Heute liegt der Anteil bei unter 50%.

Bildschirmfoto 2018-12-06 um 17.51.28

Laut unserer Formel stiegen dementsprechend die Handelsgewinne seit dem EU-Beitritt von ca. 11% auf über 20% des Pro-Kopf-Realeinkommens. Sprich: würde Österreich wieder zur Handelspolitik von vor 1995 zurückkehren, wären wir um rund 9% ärmer. Würde Österreich alle Handelsbeziehungen kappen und von nun an in perfekter Isolation leben, müssten wir auf 1/5 unseres Einkommens verzichten. Oder in absoluten Zahlen ausgedrückt: Jeder Österreicher ist im Schnitt um 8.400 Euro pro Jahr reicher durch den Außenhandel. Eine Rückkehr zu Vor-EU-Handelsverhältnissen würde jeden Österreicher ca. 3.800 Euro pro Jahr kosten.

Wie immer bei diesen Rechenspielchen sind die konkreten Zahlen mit viel Vorsicht zu genießen. Sie hängen stark von vereinfachenden Annahmen ab und bieten daher nur einen ersten groben Anhaltspunkt. Wie dem auch sei, ich mag solche Pi-mal-Daumen-Rechnungen einfach!

Economics on the beach IV: welfare optimal pricing – a model

This post builds on the previous two, economics on the beach II and economics on the beach III. I have started this, so I need to finish this now. In this post I will finally try to build a small model in which it is true that “charging a perhaps even substantial price for beach access would be welfare improving for all potential beach goers”.

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Economics on the beach II: the tragedy of the commons

There are things you want to do only with lots of other people. Go see a football game, for instance, or a pop concert. You would feel rather silly being the only one clapping and cheering. You might also prefer not to be the only couple in a restaurant. Aside from the growing feeling that you are probably in the wrong place, you miss the background chatter, the gentle clashing of dishes, the constant moving around of busy waiters. You would miss atmosphere.

But the beach, for me at least, could do with fewer people.

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