First of all, the study cited was not, in any way, any kind of an empirical study, so, no, currently there is no standard for measuring that. How does one empirically measure "moral"? One can measure any individual's feelings about what is moral, but one person's "more moral" might not be another's, so you can't really standardize that.
Schwitzgebel, himself, did not claim to be making an empirical study, as much as an interesting examination of the philosophical subject. He did a survey of opinions and looked at the results. It was an opinion poll, not an empirical study.
Version I of the questionnaire asked respondents to compare, in general, the moral behaviour of ethicists to that of philosophers not specializing in ethics and to non-academics of similar social background.
Version II asked respondents similar questions about the moral behaviour of the
ethics specialist in their department whose name comes next in alphabetical order after their own. Both versions asked control questions about specialists in metaphysics and epistemology. The majority of respondents expressed the view that ethicists do not, on average, behave better than non-ethicists. Whereas ethicists tended to avoid saying that ethicists behave worse than non-ethicists, non-ethicists expressed that pessimistic view about as often as they expressed the view that ethicists behave better.
The Moral Behavior of Ethicists: Peer Opinion - Eric Schwitzgebel and Joshua Rust, 2009
Obviously, no single study could resolve a question of this magnitude
and complexity. We decided to begin simply by asking philosophers
(both ethicists and non-ethicists) for their views on the moral behaviour
of ethicists. We asked philosophers because, more than any
other potential group of respondents, they have extensive interaction
with a broad range of ethicists and otherwise socially comparable nonethicists.
We are of course aware that responses are likely to be biased
by a number of factors and at best represent beliefs based largely on
behaviour as observed in professional contexts. However, even if peer opinion turns out only to be a mediocre indicator of the actual moral
behaviour of ethicists, philosophical opinion on this issue merits study
simply as a sociological or psychological fact in its own right, illuminating
how optimistic or pessimistic we are, as a group, about the
practical moral benefits of philosophical ethics as currently practised.
As Schwitzgebel points out himself, there's nothing inherent about examining and understanding a subject matter that requires an alteration of behavior, necessarily.
On the other hand, the connection between career and behaviour
can be tenuous and complicated. Police officers commit crimes.
Doctors smoke. Economists invest badly. Clergy flout the rules of
their religion. Whether they do so any less than people of other professions,
or any less than they would have had they chosen another career, can be difficult to assess.
While looking at people's clogged arteries would certainly inform a doctor and might make them more likely to live a healthier lifestyle (and give them more credibility in lecturing their patients), I'm sure there cardiologists who are obese and eat diets laden with saturated animal fats. Having that knowledge doesn't magically transform the behavior.
International Journal of Obesity: The effect of physicians’ body weight on patient attitudes
(Cited mostly because they examined obsese vs not-obese physicians, so there were clearly enough obese ones to sample for a study)
NY Times Blogs: When the Doctor is Overweight
By the same token, Nicolo Machiavelli was certainly a moral philosopher, but that status did not stop him from noting or even, seemingly, lauding the effectiveness of amoral, unscrupulous behavior in his most famous work, "the Prince."
The Prince is sometimes claimed to be one of the first works of modern philosophy, especially modern political philosophy, in which the effective truth is taken to be more important than any abstract ideal. It was also in direct conflict with the dominant Catholic and scholastic doctrines of the time concerning politics and ethics.
Although it is relatively short, the treatise is the most remembered of Machiavelli's works and the one most responsible for bringing the word "Machiavellian" into usage as a pejorative. It even contributed to the modern negative connotations of the words "politics" and "politician" in western countries.
Wikipedia: The Prince
There is also the very well documented and fairly universal concept of "self-justification," where, even when our actions are something we consider to be "wrong," we will find reason why that doesn't really apply in our case, if it relates to something that is particularly convenient or desirable to us as an outcome.
Immoral behavior is widespread. Here, we have outlined a framework of self-serving justifications emerging before and after moral violations that enable people to do wrong and feel moral. By distinguishing between pre- and
post-violation justifications, our framework contributes to the behavioral ethics literature and may additionally inform interventions aimed at increasing ethical conduct.
For anyone seeking to behave more ethically or encouraging others around them to do so, acknowledging the power of justifications in shaping self-serving perceptions is a key. Taming our drive to justify our behavior
may be the path to ethical conduct.
Association for Physiological Science: Self-Serving Justifications: Doing Wrong
and Feeling Moral (Shaul Shalvi, Francesca Gino, Rachel Barkan, and
Shahar Ayal, 2015
So, even when we know/believe the actions in question are not moral, we find a way to excuse it when we do it, so having that abstract knowledge, as a philosophical academician, would not necessarily translate into more moral behavior. In short, even moral philosophy professors are, first and foremost, human beings, with all the potential flaws the rest of us have.