A considerable number of employees (38 percent) do not feel their salary is adequate for their position or level of responsibility, according to the Q2 2013 Engagement Study commissioned by HR services and staffing company Randstad.

Randstad's Engagement Study biannual research shows that factors driving employee engagement must be a significant consideration for employers since the Center for American Progress estimates replacing an employee costs about one-fifth of that worker's salary.

"While employees' salaries are a significant factor in workplace satisfaction, employee engagement is not all about financial compensation. There are many nonmonetary programs employers can adopt to help improve the morale and productivity of its employee base," said Jim Link, managing director at Randstad U.S.

"As leaders in the staffing industry, we hear time and again about the positive impact training, development, and even employee recognition programs have on not only improving workplace satisfaction, but also reducing employee turnover rates. The key is finding out what factors make the most impact and what realistically your company can implement and maintain over time."

Randstad suggests rewarding high performers with bonuses and promotions, cited by study respondents as the number one tool for employee engagement and ranked as top engagement tool by 30 percent of those respondents.

To learn more about the Randstad Engagement Study and other Randstad research, visit Randstad's Workforce360 thought leadership platform.