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TedX Maastricht BrainTrain

I participated in the TedX-Maastricht BrainTrain event: a talk on
OddSpot in the Amsterdam-Maastricht train “in a Ted-talk kind of way”. Well ...

Sort of a surreal experience, including a line-up of speakers ranging from serious to sort of strange, and as usual I managed to look totally weird on the pictures taken (I hope). Because Powerpoint slides could not be used, I put some slides on two t-shirts, which seemed to work out quite well:



PS I finished the talk with Paul Meehl’s famous quote, but changed a couple of words along the way. Below - for completeness sake - what I said and the original quote:

what I said:
There is no controversy in social science [that] shows such a large body of qualitatively diverse studies coming out so uniformly in the same direction as [the comparison between human experts and formal models]. When you [have tested] everything from the outcomes of football games to the diagnosis of liver disease and when you can hardly come up with a half dozen studies showing even a weak tendency in favor of the [expert], it is time to draw a practical conclusion.

the original (quite close):
There is no controversy in social science which shows such a large body of qualitatively diverse studies coming out so uniformly in the same direction as this one. When you are pushing [scores of] investigations [140 in 1991], predicting everything from the outcomes of football games to the diagnosis of liver disease and when you can hardly come up with a half dozen studies showing even a weak ten- dency in favor of the clinician, it is time to draw a practical conclusion.

Social orientation measurement using 1 question

The Social Orientation Value (SVO) is a measurement of someone’s “social preferences”. Literally, it is meant to measure the extent to which you care about what others get. Often, It is measured through the “RING measure” (a tedious procedure with many questions), or through a series of decomposed games. In this latter method, you typically get 9 comparisons and are classified as egoist, altruist or competitor if you choose consistent with that label at least 6 out of 9 times.

I often come across papers or presentations where SVO is measured, and usually I manage to remember that a long while ago, Jeroen Weesie and me came up with a single question measure for the social orientation value (as part of the HIN95Exp booklet). We published about this in a Dutch book, Kalmijn et al. (1999) Huwelijks- en samenwoonrelaties in Nederland. De organisatie van afhankelijkheid. ISBN13: 9789023234524

If I remember correctly, we had a chapter in there about the effects of having (dis)similar time preferences and (dis)similar social value orientations on the extent of marital problems.

Unfortunately, although I remembered how we did it, I could not find the data back. Today I did! It worked as follows. The single question we used was:

We present you a situation in which you have to choose between 4 possible payments to you and a random other participant in this survey:

you get--------the other gets--------your choice
1)  69 24  .
2)  61 55  .
3)  78 13 .
4)  64 34 .

We like to know how attractive you consider each of these possibilities. Look careful at the possibilities. Put a "1" behind the option that you consider most attractive. Now, put the number "4" behind the option that you find the least attractive. Now put a "2" behind the option that you find most attractive of the two remaining options. Finally, put a "3" behind the one option that is left.

The smart bit about it is that it is actually asking for six comparisons simultaneously. Assuming that the SVO-value equals x, you prefer the first over the second option if 69+24x > 61+55x, which happens if and only if x<8/31. The six implicit comparisons are (I hope I did the math right):

1>2 <=> x<8/31 => threshold at 0.26
1>3 <=> x>9/11 => threshold at 0.82
1>4 <=>  x<1/2   => threshold at 0.50 
2>3 <=>  x>17/42 => threshold at 0.40
2>4 <=>  x>1/7  => threshold at 0.14
3>4 <=>  x<2/3  => threshold at 0.67

So depending on your SVO, you rank these four options differently.

              4/2             1/2              3/2               1/4             3/4               3/1


If 0.00{X{0.14, 4>2, 1>2, 3>2, 1>4, 3>4, 3>1 --->> 3>1>4>2, input should be [2413]
If 0.14{X{0.26, 4<2, 1>2, 3>2, 1>4, 3>4, 3>1 --->> 3>1>2>4, input should be [2314]
If 0.26{X{0.40, 3>2>1>4, input should be [3214]
If 0.40{X{0.50, 2>3>1>4, input should be [3124]
If 0.50{X{0.67, 2>3>4>1, input should be [4123]
If 0.67{X{0.80, 2>4>3>1, input should be [4132]
If 0.80{X, 2>4>1>3, input should be [3142]

Note that there are inputs by participants that are not consistent with choosing in accordance with SVO. For instance, the input [1234] suggests that the first option is preferred over the second (x<0.26) and the first over the third (x>0.82), which is a contradiction.

From the data analysis that we did at the time, I remember that our SVO-values were consistent with what was found using the other methods, including that 15 or 20% or so could not be properly classified.

For some reason, we thought that SVO-values might be larger than one as well, and also included:

1)  31 72
2)  22 80
3)  59 64
4)  41 67

1>2 <=> x<9/8 => 1.13
1>3 <=> x>7/2 => 3.50
1>4 <=>  x>2 => 2.00
2>3 <=>  x>37/16 => 2.31
2>4 <=>  x>19/13 => 1.46
3>4 <=>  x<6 => 6.00

but I don’t think we had many people with such high SVO’s.

A true comparison (within person?) would still be useful, I guess. But nevertheless, having this as an option might be good value to use in already long surveys. Running it twice, the second time with slightly different numbers, would also give nice test-retest values. So use at your own risk. If it is of use: credit where credit is due please!

Paper on process-performance paradox

Frits Tazelaar and yours truly got a paper accepted in Journal of Operations Management. It is about the “process-performance paradox”, and based on a combination of our dearest MAT-2003 database in combination with conjoint analysis.

We consider the “process-performance paradox” in the assessment of operational risks by profession- als in the field of operations and supply chain management (OSCM). The paradox states that although professionals with more expertise tend to decide in different ways, they often do not make better assessments than those with less expertise. We first replicate that this paradox exists in a context of the assessment of operational supply risks, and then show how the paradox can be understood as the consequence of process characteristics mediating the relation between expertise and assessment performance.
Using an experimental setup, we had 234 OSCM-professionals assess the operational risk in two series of different business cases, and measured several characteristics of their decision-making process. The strength of our approach lies in the fact that the business cases were real-life cases from our database of purchasing transactions in the area of IT-purchasing. This allows a comparison of the risk assessments of the professionals with the actual supply risk as was known from the survey database. Our findings show that, contrary to what is often assumed, the OSCM-professionals with more expertise do not use less information while assessing, nor are they faster. Instead, our results show that specialized expertise goes with increased certainty about the assessments, and general expertise goes with an increased use of intuitive judgment. However, the net effects of these expertise characteristics on assessment performance are zero. In the case of specialized expertise this is because specialized expertise is itself negatively related to performance. In the case of general expertise this is because the net effects of the use of intuition on performance are zero.


Ik heb geen succes met columns. In de cursor - het lokale blaadje van de TU/e - schrijven wij HTI-ers om beurten een column. Naar aanleiding van de zaak Vaatstra ging de mijne over dat het toch nog moeilijk is om op basis van een match met een DNA profiel de kans te berekenen dat iemand schuldig is. Dat kwam terug met de kwalificaties “warrig geschreven”, je mag niet naar een boek verwijzen zonder het te noemen, en “ik mis het leermomentje”. Het moest in 300 woorden, dus misschien is het wat compact, maar helemaal onzin is het toch niet, en een leermomentje zit er volgens mij wel degelijk in. Maar oordeel vooral zelf:


Als een krant

Kort geleden schreef Rense Corten een goed doorwrocht commentaar op het stukje “De Kloof is Wit” in de Volkskrant. Dat moet je niet doen natuurlijk, dat vond de Volkskrant ook

“Het is een wetenschappelijke kritiek op een journalistiek artikel. Behalve de vermenging van beide genres is de kans ook erg groot dat het over de hoofden van de lezers heengaat, zoals dat heet.”

Ja, zo heet dat. Op de bank voor de tv schoot me de wetenschappelijke nonchalance van het originele stukje in het verkeerde keelgat, en paste het commentaar van Corten aan op een manier die natuurlijk eigenlijk ook niet hoort: rare titel erboven, verwijzing naar Stapel erbij, het ingewikkeldste tegenargument er uit, wat moppige verwijzingen naar het origineel erbij, en een op zich wel terechte maar beetje vervelende sneer uitdelen:


Die had er wel in gemogen.