Researchers at Rice University and the University of Houston say letters of recommendation – intended to help women in their business careers – may instead have the opposite effect.

They contend such letters written for women are more likely to contain words or phrases that raise doubts about job or education qualifications than letters written for men.

Raising Doubt in Letters of Recommendation for Academia: Gender Differences and Their Impact” is available online and will appear in an upcoming print edition of the Journal of Business and Psychology. The research was led by Mikki Hebl, the Martha and Henry Malcolm Lovett Professor of Psychology, and her former graduate student, Juan Madera, now an associate professor of hospitality management at the University of Houston. 

The researchers defined “doubt-raisers” as phrases or statements that question an applicant’s aptness for a job. This language falls into four categories: negativity (directly saying something bad), faint praise (indirect criticism of someone or something by giving a slight compliment), hedges (cautious or vague language) and irrelevant information (going off in a direction unrelated to the job description). Examples of doubt-raisers are statements like “the candidate has a somewhat challenging personality” or “she might be a good leader in the future.”

The first study revealed that, on average, letters written for women were more likely to contain a doubt-raiser than letters written for men (regardless of whether a man or a woman wrote the letter). This was true for negativity, hedging and faint praises but not for irrelevancies. Hebl notes that doubt-raisers are not extraordinarily uncommon — on average, more than half of the letters contained at least one. She also notes that such wording might weigh in on decisions in which candidates otherwise have very similar qualifications.

“Letters of recommendation are usually so positively skewed to begin with that a ‘doubt-raiser’ can stand out in a sea of positivity,” Hebl said. “Also, recommendations are made all the time, even if they’re not in letter form. It’s so important to think about the ways language reflects subtle biases, as these spoken subtleties also may add up over time to create disparities.”

In the second study, the researchers examined whether people actually recognized and were influenced by a doubt-raiser within a recommendation letter. Approximately 300 university professors across the country were asked to rate one recommendation letter. Letters were manipulated to have just one of the four doubt-raisers and to be written for either a man or woman; all other information contained in the letter was identical across conditions.

The researchers found that the presence of any one of three doubt-raisers negativity, faint praise or hedges caused the professors to rate these letters negatively. The fourth doubt-raiser, irrelevant information, made no difference in how the letters were rated.

I would suggest avoiding these types of phrases in recommendations if you are trying to write a strong letter,” Hebl said, “and to be aware that they might be more likely to unintentionally slip into letters for women than men.”

Tom Schuman is the senior vice president of communications & operations for the Indiana Chamber. He is also the editor of the Chamber’s award-winning BizVoice magazine and has been with the organization for 20 years.