Last year, a new study on green innovations and patents in 27 countries left one reader slack-jawed. The findings were no surprise. What was baffling was how the authors, two professors of economics in Europe, had pulled off the research in the first place.
The reader, a PhD student in economics, was working with the same data described in the paper. He knew they were riddled with holes – sometimes big ones: For several countries, observations for some of the variables the study tracked were completely absent. The authors made no mention of how they dealt with this problem. On the contrary, they wrote they had “balanced panel data,” which in economic parlance means a dataset with no gaps.
“I was dumbstruck for a week,” said the student, who requested anonymity for fear of harming his career. (His identity is known to Retraction Watch.)
The student wrote a polite email to the paper’s first author, Almas Heshmati, a professor of economics at Jönköping University in Sweden, asking how he dealt with the missing data.
In email correspondence seen by Retraction Watch and a follow-up Zoom call, Heshmati told the student he had used Excel’s autofill function to mend the data. He had marked anywhere from two to four observations before or after the missing values and dragged the selected cells down or up, depending on the case. The program then filled in the blanks. If the new numbers turned negative, Heshmati replaced them with the last positive value Excel had spit out.
The student was shocked. Replacing missing observations with substitute values – an operation known in statistics as imputation – is a common but controversial technique in economics that allows certain types of analyses to be carried out on incomplete data. Researchers have established methods for the practice; each comes with its own drawbacks that affect how the results are interpreted. As far as the student knew, Excel’s autofill function was not among these methods, especially not when applied in a haphazard way without clear justification.
But it got worse. Heshmati’s data, which the student convinced him to share, showed that in several instances where there were no observations to use for the autofill operation, the professor had taken the values from an adjacent country in the spreadsheet. New Zealand’s data had been copied from the Netherlands, for example, and the United States’ data from the United Kingdom.
This way, Heshmati had filled in thousands of empty cells in the dataset – well over one in 10 – including missing values for the study’s outcome variables. A table listing descriptive statistics for the study’s 25 variables referred to “783 observations” of each variable, but did not mention that many of these “observations” were in fact imputations.
“This fellow, he imputed everything,” the student said. “He is a professor, he should know that if you do so much imputation then your data will be entirely fabricated.”
Other experts echoed the student’s concerns when told of the Excel operations underlying the paper.
“That sounds rather horrendous,” said Andrew Harvey, a professor of econometrics at the University of Cambridge, in England. “If you fill in lots of data points in this way it will invalidate a lot of the statistics and associated tests. There are ways of dealing with these problems correctly but they do require some effort.
“Interpolating data is bad practice but lots of people do it and it’s not dishonest so long as it’s mentioned,” Harvey added. “The other point about copying data from one country to another sounds much worse.”
Søren Johansen, an econometrician and professor emeritus at the University of Copenhagen, in Denmark, characterized what Heshmati did as “cheating.”
“The reason it’s cheating isn’t that he’s done it, but that he hasn’t written it down,” Johansen said. “It’s pretty egregious.”
The paper, “Green innovations and patents in OECD countries,” was published in the Journal of Cleaner Production, a highly ranked title from Elsevier. It has been cited just once, according to Clarivate’s Web of Science.
Neither the publisher nor the journal’s editors, whom the student said he alerted to his concerns, have responded to our requests for comment.
Heshmati’s coauthor, Mike Tsionas, a professor of economics at Lancaster University in the UK, died recently. In a eulogy posted on LinkedIn in January, the International Finance and Banking Society hailed Tsionas as “a true luminary in the field of econometrics.”
In a series of emails to Retraction Watch, Heshmati, who, according to the paper, was responsible for data curation, first said Tsionas had been aware of how Heshmati dealt with the missing data.
“If we do not use imputation, such data is almost useless,” Heshmati said. He added that the description of the data in the paper as “balanced” referred to “the final data” – that is, the mended dataset.
Referring to the imputation, Heshmati wrote in a subsequent email:
Of course, the procedure must be acknowledged and explained. I have missed to explain the imputation procedure in the data section unintentionally in the writing stage of the paper. I am fully responsible for imputations and missing to acknowledge it.
He added that when he was approached by the PhD student:
I offered him a zoom meeting to explain to him the procedure and even gave him the data. If I had other intensions [sic] and did not believe in my imputation approach, I would not share the data with him. If I had to start over again, I would have managed the data in the same way as the alternative would mean dropping several countries and years.
Gary Smith, a professor of economics at Pomona College in Claremont, California, said the copying of data between countries was “beyond concerning.” He reviewed Heshmati’s spreadsheet for Retraction Watch and found five cases where more than two dozen data points had been copied from one country to another.
Marco Hafner, a senior economist at the RAND Corporation, a nonprofit think tank, said “using the autofill function may not be the best of ideas in the first place as I can imagine it is not directly evident to what conditions missing values have been determined/imputed.”
Hafner, who is research leader at RAND Europe, added that “under reasonable assumptions and if it’s really necessary for analytical reasons, one could fill in data gaps for one country with data from another country.” But, he said, the impact of those assumptions would need to be reported in a sensitivity analysis – something Heshmati said he had not done.
“At the bare minimum,” Hafner said, the paper should have stated the assumptions underlying the imputation and how it was done – something that, he added, would have reduced the chances of the work getting published should the reviewers find the methods inappropriate.
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Imputation has been around for many decades. It permits the researcher to study, say, five predictor variables when one of the predictor variables shows incomplete sampling. As long as its use is described in methods, it is a reasonable procedure.
As long as. Pulling in numbers from adjacent cells (countries next or following in the alphabet) without acknowledgement is not reasonable in any meaning.
Correct.
If you take two census bureau data sets, for example, one will likely not have all the counties of another. R’s MICE program imputes the missing data cells.
This is a failure to use competent statistical assistance, not plagiarism or outright fraud. Even competent statisticians will make errors. Statisticians can disagree about which statistic to calculate.
Some imputation is reasonable and defensible and some is not. Depends how you did it. This professor needs to read a book on imputation since the methods described are terrible on their face. The lack of transparency in the article makes it much worse.
“If I had other intensions [sic] and did not believe in my imputation approach, I would not share the data with him.” The student was lucky he got any data whatsoever. Despite data sharing statements in publications most authors do not share raw data, nor are there any practical mechanisms for compelling them to do so when, for example, wishing to collect raw data to perform a meta-analysis.
Why not use EM algorithms!
These procedures seem highly questionable, especially copying data for one country to another one without disclosure. As an economic historian I have often worked with country data sets, but never even dreamed about this kind of “imputations”. I am sure this is not the first time the professor has “massaged” the data beyond the breaking point. Full check on all his work, including plagiarism, please.
I think it’s embarrassing this article passed peer review. This, to me, is evidence of why we need methodological pre-registration and peer review *before* results are sought. It would at the very least invalidate this shoddy analysis and/or might have forced the author to rethink their approach.
It’s true that once you start inventing data you did not measure, you enter a certain realm of incredulity. If you explain in your paper that you chained a monkey to a typewriter and did analysis on the resulting gibberish, then your analysis could be technically correct but it would still be utterly useless (GIGO). If you’re going to make up observations, at least attempt to make them defensible, or at least grounded in a sensible model. That way your results are only a partial departure from reality. 😏
As a statistician, I find this appalling. Yes, there are times where imputation is useful. However, what this professor did bears no resemblance to any reputable imputation method and it’s *never* acceptable to do imputation without describing what you’ve done in the methods section of the paper. There’s no way a valid, reliable analysis could have been done on a dataset with that much fake data.
Kudos to the student for being so attentive, proactive and investigating what had been done to the dataset. It’s very intimidating for someone junior to question the work of senior established researchers, but it’s important for such sloppy work to be retracted/corrected.
Thank you for removing nonsensical content from this discussion. Yes, the lack of transparency and lack of algorithm makes this paper nonsense. The student did what is right and important. Trash needs ot be removed more often.
what percentage of the dataset was imputed?
Roughly 133%. (This figure is also imputed. Details on request.)
According to the article – “ This way, Heshmati had filled in thousands of empty cells in the dataset – well over one in 10”
Questions from a layperson. If the method is bad, then why is documenting it with “I used this method” any better than the alternative? Both situations use the bad method, so the only way to improve is to use a better method, correct? Wouldn’t it have been better for the author to use modern GPT for this procedure instead of Excel?
If it’s documented, everyone can judge the results based on the method being bad… starting with the reviewers, who might well have rejected the paper.
I do not like the idea of making the reviewers the victims here.
It is not only the author’s fault that they did not disclose their methods. The reviewers obviously did not care either.
Looks more like this whole discipline has a serious problem.
It is not like the authors lied about their methods or tricked the reviewers. The reviewers obviously just did not bother to check the results as carefully as this one student (!) did.
Documentation lets the peer reviewers and readers decide if the method is good or bad. We need to know where the numbers came from to decide how much trust to place in the paper’s conclusions.
If he’d documented it then this would have been just a bad piece of research (and hopefully not pass peer review) but not academic dishonesty. By generating the numbers but claiming they are measured values, he crosses the line to dishonesty.
Using a GPT would be worse. At least with Excel the numbers have some relation to the measured values. A GPT would just make up data that looks plausible.
I guess using GPT is the only thing worse than using Excel without mentioning. There’s no chance to know how GPT has come to it’s values.
Disclosing it is better than the alternative because it can then at least be questioned. Reviewers can ask for a justification or perhaps recommend rejection, readers can take the results with a pinch of salt or possibly make their own conclusion that “come on, this is bullshit”, etc, while without disclosure the assumption is that it’s not been done and the dataset is clean.
Using GPT would be far worse. With the Excel method, the researcher mostly knows (or can know) how the values were imputed, and can describe the procedure; there is no way to know with GPT, and it would change from version to version as GPT is updated (or even due to randomness in response to prompts).
They’re using the data they imputed to claim a result from their data is a valid understanding of how to understand this reality based on values they provided in the paper.
But it harms their conclusion if they say “A lot of this data is interpreted from the other data, and not actually taken from the implied source.”, which is why they didn’t say it. There’s significantly less relationships between their data and reality, so they’re not actually saying something that is actionable…despite being cited for something else already.
That’s going to be an issue for replication studies if they end up going “We don’t know how they got this data.”
To “Humbry” — note the following in the original post, indicating the student *already* had the data — “The reader, a PhD student in economics, was working with the same data described in the paper. He knew they were riddled with holes – sometimes big ones:”
Imputation makes nonsense of the statistical-fit results they report.
If you want to play with confected data, go ahead, and if a journal wants to indulge you, fine. But read section 5 of the article! They are making numerous claims of statistical significance, correlation etc. If those claims are based on made-up data they are false, period, no matter what they disclose.
This is profoundly dishonest. Goodness of fit often makes the difference between being publishable and not.