A study published by the American Psychological Society in the Journal of Personality (5th February 2007) claims that Leaders who exhibit either high or low assertiveness tendencies are less effective leaders than those who rank a more average or 'optimal' assertiveness behaviour pattern. The results of this study suggest that being over or under assertive are the most common weaknesses in our Leaders today.

In this study by Daniel Ames PhD and Francis Flynn PhD workers were asked their opinion on the strengths and weakness of their organisation's leaders. Charisma, intelligence, and self-discipline were among the top positive traits mentioned but the most common sited problem was assertiveness. Ames and Flynn coded the responses from nearly one thousand workers about their leader's behaviour. The most common adjective in the comments about weaknesses was 'assertiveness'. 'Assertiveness' was used over double the amount as 'able' or 'focused'. Of those who cited assertiveness to be a problem almost half said their leaders were too assertive and the remainder said not assertive enough. The references to assertiveness were much more common in the comments about leadership weaknesses than in those about leadership strength

According to Ames, "When leaders get assertiveness wrong, it's glaring and obvious, but when they get it right, it seems to disappear," he continues "We say it's like salt in a sauce: when there is too much or too little, it is hard to notice anything else, but when it's just right, you notice the other flavours. No one compliments a sauce for being perfectly salted, and it's just as unusual for a leader's perfect touch with assertiveness to attract much notice."

Ames and Flynn analysed their findings to find out why assertiveness was perceived to be such a problem in leadership roles. At one end of the spectrum they suggest that Leaders low in assertiveness are ineffective at achieving goals, motivating others, meeting deadlines and achieving results. Leaders who are very assertiveness are difficult to work with, do not listen, they do not communicate well and find it difficult to form good relationships.

Although Ames and Flynn warn against the idea that leaders should moderate their assertiveness at all times, they recommend that leaders recognise when they need to be more or less assertive, knowing when to be considerate and when to stand firm. They also recognise that to be seen as being moderately assertive is the key to a cooperative workforce. The secret is not to be too assertive on not assertive enough all of the time. Ames and Flynn claim that many leaders are surprised how their co-workers see them, often being unaware of how their behaviour affects others. Leaders are advised to look at the key assertiveness skills and give themselves an honest appraisal of how they fair. Employees will seldom approach a leader to ask him to take a look at his assertiveness levels.