The most important factor in the success of an employee survey is having a clear idea of the survey’s objective. What specific business outcomes do you wish to achieve through the research?
You also need a basic understanding of the workforce before deploying an employee survey. Do most employees have access to email and the Internet? If so, then an online survey deployment may be appropriate with some smaller number of paper surveys. If not, then paper or telephone surveys or a combination may be your only choices.
Language is also a consideration. Do you need one language or multiple languages?
If it’s a global survey, you need to understand local and regional holiday schedules. Sending a survey to Europe in August or sending it anywhere during the Holy Days of the area’s primary religion will not produce the responses you need because employees may not be able to respond.
In general, make sure you set objectives for the research, make sure that the survey questions and responses are actionable, and make sure employees can receive and understand the survey.