On bats and rabies

The recent JAVMA News article¹ pointing out that bats are the leading rabies vector in the United States was a timely reminder that bats pose a risk of causing rabies and that avoiding contact with bats and other wildlife is one of the best ways to protect oneself from rabies. However, it is important to remember that human rabies is rare in the United States, with only one to three cases reported annually and only 42 cases reported in the United States between January 2003 and October 2018.² Of the 125 human rabies cases reported in the United States between 1960 and 2018, roughly a quarter resulted from dog bites during international travel.³ On the other hand, 70% of infections acquired in the United States were attributed to bats.

Despite this risk, it is also important to remember that few bats carry rabies and that bats consume vast numbers of insects, including some of the most damaging agricultural pests. A 2015 study,⁴ for example, estimated that bats are worth > $1 billion to the global corn industry on an annual basis.

Bats are state and federally protected animals, and it is illegal to exterminate or poison bats in Michigan. More importantly, bats play a vital role in the ecosystems of the world, and our planet would not be the same without them.

Charles Ryan, dvm, mph

Traverse City, Mich

Goodhart's law in veterinary medicine and education

In recent years, US veterinary colleges have made considerable strides in the field of medical education. There are increasing numbers of professional development opportunities for educators, greater turnout at education-related meetings, increased interest in educational scholarship, development of regional consortia that focus on educational collaboration, a rising number of educator academies, and much more. With each of these steps forward come new opportunities to measure growth and change in veterinary education. However, as leaders in veterinary education continue to discuss what these measures might look like, it is important to remember Goodhart's law, as its implications for veterinary education are substantial.

Goodhart's law is named after the renowned economist Charles Goodhart and has been phrased as “when a measure becomes a target, it ceases to be a good measure.”^1,2 Essentially, this refers to the fact that whenever a target measure is declared, actions will be taken to ensure the target is met, regardless of how those actions affect the overall outcome. When this occurs, both the integrity of the intended target and its utility as an outcome measure are compromised.

Examples of how target measures can be manipulated are well documented in a variety of fields. For example, in scientific research, a P value < 0.05 has long been considered one of the key determinants of a discernible difference, change, or successful intervention (ie, “statistical significance”). Yet, it is well documented that a variety of factors (eg, sample sizes that are too large or too small) may influence the P value. Thus, when statistical significance became the target, the value of many studies was lost, especially those with important findings that were, nonetheless, not statistically significant.

In health care, policymakers argued that decreasing waiting times in emergency rooms would save more patient lives. Emergency rooms subsequently created a target of reducing waiting times to less than four hours. According to Campbell et al,³ the result was that hospitals often triaged patients differently to avoid certain patients being counted, kept patients waiting in ambulances, or rushed to admit patients nearing the four-hour deadline. Despite successful achievement of the target measure, there was little, if any, impact on patient lives.

In veterinary practice, there are numerous examples of Goodhart's law. Sales targets were met, but only after offering profit-reducing discounts or coupons. Website hits were increased, but only because search engine optimization strategies were implemented. Hiring incentives intended to increase the number of qualified applicants primarily attracted individuals with economic motivations.

In veterinary education, we can similarly anticipate some measures that may be vulnerable to Goodhart's law. For example, continuing education credits, resident duty-hour guidelines, and accreditation standards all impose some target (minimum or maximum) values. Familiar scientific metrics such as P values and impact factors may obfuscate quality measurement.

As we work together to build the most robust programs and policies possible, it is imperative that we remain cognizant of the many ways in which target outcome measures may be manipulated, both intentionally and innocently. It is only then that we can achieve outcome measurements that are truly meaningful.

Kenneth D. Royal, phd, msed

Department of Clinical Sciences College of Veterinary Medicine North Carolina State University Raleigh, NC

Rethinking bans on cat declawing

New York recently became the first state to outlaw cat declawing,¹ although other communities have previously outlawed this procedure. In my opinion, however, outlawing declawing is not in the veterinary profession's best interest and could potentially lead to outlawing other veterinary procedures.

On top of that, I wonder how much of the opposition to declawing is based on anthropomorphic concerns, rather than assessments of anatomy and outcome. For example, the vast majority of the distal phalanx (P3) is covered by the claw, making it likely that P3 does not play an important role in normal ambulation in cats. And, although various tendons and ligaments attach to P3, these structures function mainly to keep the claws retracted. Thus, I contend that removing P3 likely has little impact on ambulation in cats. Determining whether this is the case might be a good research project for a veterinary college.

Of course, postoperative problems can occur following declawing, but such problems do not seem to be particularly common, and the vast majority of owners appear to be happy with the outcome and do not perceive any lasting or chronic issues. Postoperative complications can occur with any surgical procedure, and poor surgical technique is unacceptable regardless of the procedure performed.

Ultimately, the decision of whether to declaw a cat—or, for that matter, whether to spay or castrate a cat or to perform any other surgical procedure—should be left up to the owners after a thorough discussion with their veterinarian regarding the risks and benefits of the procedure, potential alternatives to the procedure, and likely outcomes with and without the procedure. This makes infinitely more sense than banning specific procedures. In the right setting, declawing can be a valuable surgical procedure that benefits both the cat and its owner and strengthens the human-animal bond. These sensitive and important decisions need to be left to owners and their veterinarians.

Robert J. Neunzig, dvm

Dallas, NC