There are two measurements involved in the assessment of a manager's soft skills, just as there are when measuring quality.
First, there is measurement of the manager's compliance with using soft skills. This requires precisely defining those skills just as one would define quality standards.
Second, there is measuring the effect of the result of the use of soft skills or the use of quality standards. This would mean measuring productivity resulting from the use of soft skills, just as one would seek increased sales and consumer satisfaction as a result of quality controls.
I think that we know how to make the second measurements, but we don't have defined metrics for soft skills. As a starting point, I would recommend a simple test consisting of the 10 questions below. Rank a manager on a scale of 1 to 10 with 10 being the best or almost always performs the action and 1 being the worst or almost never performs the action. Add up the points for each question. If the score is close to 100, I would expect that employees will be over 3 times more productive than if the score was 30 or less. In addition, with a score close to 100, employees will unleash their full creativity and innovation, love to come to work and have very high morale.
Does the manager:
- Provide regular and frequent opportunities for employees to voice complaints, suggestions and questions, provide reasonable and timely responses, and give employees what they say they need to do a better job? (At least weekly?)
- Elicit answers/responses from the team and get them to use their brainpower to solve problems?
- Listen to employees with 100% attention without distraction, without trying to figure out a response and with the use of follow-up questions to obtain missing details and suggested fixes?
- Refrain from giving orders since by their nature they demeaning and disrespectful and destroy innovation and commitment?
- Treat members better in terms of humility, respect, timely and high quality responses, forthrightness, trust, admission of error, etc than they are expected to treat customers and each other?
- Publicly recognize employees for their contributions and high performance and never take credit him/herself?
- Openly provide all company info to employees to the extent they need/desire?
- Use values and high standards of them in order to explain why certain actions are better than others?
- Use smiles and good humor with subordinates, not frowns or a blank face?
- Generate in employees a sense of ownership?
Remember that leadership is science and thus the results of your leadership are fully measurable and every manager, executive, boss should go about setting and reaching leadership metrics. The impact on your organization in terms of ROI has been proven to be considerable. With attention paid to the areas listed above, you can increase productivity, retention, innovation, creativity, morale, and revenue.