Psychologist John Gottman can tell whether a married couple is more likely to last or end in divorce. In a study over several years, he found that the happiest couples said or did at least five positive things for every one negative interaction they had. They were more likely to stay together.

In contrast, the couples whose criticisms outweighed compliments by about three times were more likely to split up. At the workplace too, it seems that employees should hear more positive feedback than criticism to perform optimally. Researchers Margaret Greenberg and Dana Arakawa, in a study with the University of Pennsylvania, found that managers who gave frequent recognition and encouragement had better project performance. Those who gave the most frequent recognition and encouragement saw a 42% increase in productivity from staff.

Why is positive feedback so powerful? Besides helping people learn and build on what they are doing well, “it also builds positive emotions related to work, which lead to better performance,” says corporate consultant Vadivu Govind, founder of Joy Works. “It can enable flourishing relationships.”

At the workplace, however, constructive criticism is necessary for improving performance or changing behaviour. Positive feedback and experiences built up over time create a buffer against any negative feelings that arise from hearing critical comments. Similarly, in the case of married couples, Professor Gottman found that the happiest were able to create a sense of trust, respect and appreciation, he told The Atlantic. The unhappy ones, meanwhile, were always on the lookout for mistakes, creating hostility instead.

So managers should take care to give more compliments than criticism. But avoid giving positive feedback only when delivering negative feedback, or sandwiching criticism with praise, a move that can be seen as inauthentic by employees savvy to this tactic.

Find yourself unable to think of anything good to say? Ms Govind suggests being more observant. “If we are doing things at great speed and are distracted, we can miss many opportunities for observing behaviours that merit positive feedback.”

And when it comes to giving negative feedback, her advice is to give it with sensitivity, skill and the right intention: “Never to harm but to help others grow.”