In 1981 I was appointed as a professor of economics at the University of Amsterdam. One of my colleagues was Joop Klant, professor of economic methodology. When he retired, in 1986, at the farewell dinner, he reminded us of his opportunity cost: we received a copy of his novel De fiets (The bicycle), a booklet that had brought him literary fame in his youth. He signed my copy with the encouragement: “Test, test, test, Hartog: never stop”. Yes, we shared a belief in the Popperian assignment and I have been trying to test theory whenever I could. In fact, the paper I am now working on is an empirical test of the theory that employers safeguard young graduates from wage reduction when their productivity turns out below standard (the present verdict is: reject!).
In 1994, my friend Jules Theeuwes and I launched the journal Labour Economics. We wanted a balanced mix of theory and empirical work and we opened a separate section for Replications, with a separate editor. As replication submissions were barely forthcoming (one paper in 3 years), we decided to beat the drum. We were firm believers. “The basic premise of econometric research is the existence of stable parameter values in equations that relate economic variables. Yet, we do not have a great deal of information about parameter values and their empirical distributions”, we wrote in 1997 as introduction to a set of invited papers on replication (Labour Economics, 4(2), 99). We guaranteed publication of replication studies, provided they would meet some mild conditions (aim to replicate key findings of an original article in a leading journal, and contain no methodological flaws).
To our regret, we never got a single submission. We understood the reason quite well. Replication does not lead to academic prestige. There are some famous cases of replications that failed to reproduce the original findings (Harberger’s tax on capital, the Journal of Money, Credit and Banking Project, see our Labour Economics introduction), but basically, the profession and in particular journal editors, were not interested. But the times, they are a’changing.
Interest in the reliability and credibility of empirical work has been mounting. For nine years, I have been a member of LOWI, a national board for research integrity founded by Dutch universities and The Netherlands Academy of Sciences. It’s a board of appeal on university rulings on research integrity. When we started, a decade ago, we got a few cases annually. In 2014 the board got 24 cases, generally much more serious than initially, with heavy impact on the accused. In The Netherlands we experienced some spectacular cases of data fraud (not in economics though) and awareness of the ofen very shaky basis of econometric results has strongly increased. The dangers of an emphasis on originality, on new methods, new models, new approaches, rather than on the painstaking patient search for reliable, reproducable results are now clearly appreciated. Data must be made easily available. I remember a phrase that struck me long ago: “Often, a researcher’s mind is more fruitful than his database”. Data transparancy and a new attitude should change that.
Some time ago, it occurred to me that professional organisations or journals should create a replication archive. I mentioned that, visiting Waikato University, to Jacques Poot, who told me: my dear friend, that exists! An excellent initiative. It proves again that the new day starts in New Zealand: that ‘s where the sun first rises.
Here’s evidence on my sincerity:
Arulampalam, J. Hartog, T. MaCurdy and J.Theeuwes (1997), Replication and re-analysis, Labour Economics, 4(2), pp. 99-105
Cabral Vieira, L. Diaz Serrano, J. Hartog and E. Plug (2003), Risk compensation in wages: a replication, Empirical Economics, 28, pp. 639-647
Mazza, H. van Ophem and J. Hartog (2013), Unobserved heterogeneity and risk in wage variance: Does more schooling reduce earnings risk? Labour Economics, 24 (), 323-338
Budria, L. Diaz Serrano, A. Ferrer and J. Hartog (2013), Risk Attitude and Wage Growth, Replicating Shaw (1996), Empirical Economics, 44 (2), 981-1004