Communication is the single most important factor in success or failure. If you’re a manager, your communication skills come into play in many situations: formal reviews, company meetings, informal feedback, as well as face time with clients or upper management.

Providing essential information about an employee’s performance in a way that focuses on outcomes—not personalities—can mean the difference between getting a high-profile assignment done correctly or potentially losing a key employee or client.

Of course, not all communication happens verbally. A famous study (Harris/Osborne) in the 1970s found that only 7 percent of communication happens with words; 38 percent of messages are gleaned through perceptions of voice, including tone, rate, and inflection; and a whopping 55 percent of communication happens through face and body language. So if you’re still frowning about some mishap at home once you hit the office, employees may interpret your facial expression as evidence of displeasure you have about their job performance.

Tom’s Takeaway: Communication stakes are high. Leaders need to take the time and make the effort to develop strong communication skills, including verbal and nonverbal strategies.