Dear John,
Apart from direct one-on-one intervention by an experience therapist, councilor or psychologist , there is no definite tool in analyzing stress. This is because an admission of stress, even subconsciously, can cause more stress. I believe that every company must conduct a stress management workshop or rather what I call a "happiness management workshop" twice a year. It is like taking a laxative once a while to clean your digestive system. One shouldn't wait for a disease to occur to maintain good health. For better health, we should attend "heath management" workshops regularly and not "disease management" workshops when we are sick, right?
If someone claims to have a questionnaire-based stress analysis tool, he is just offering you waste paper. You'll get far better results reducing stress by using the money to distribute food to the hungry by the hands of your employees.
If you think your employees are stressed then they definitely are. Don't waste anymore time and have them attend a stress management workshop by which they can cope with their stress or eliminate it for the short term. Then you should have them attend workshops on team building, creating and maintaining relationship (both personal and professional), time management and goal setting. These workshops will help prevent future causes stress.
One important note for any stress management workshop - people do not need to know ALL the causes of stress. Unfortunately, this is done at most stress management workshops. Participant might end up unconsciously learning new ways of getting stressed. We wouldn't want that happening, would we? ;-)
Hope these tips help
Avinash Tavares
youthempowermentsolutions(dot)org