If you've done research, you know what it's like to be paranoid. It takes this form: "Right now, somebody is doing the exact same research or writing that I'm doing, only they're doing it better and faster."
You may have experienced this phenomenon when the newer graduate students copy some of your procedures, or tackle the same subject. Or somebody mentions that they think so-and-so is doing similar research. What follows is usually sleepless nights, hair-pulling days, and breathless investigation into the truth of the rumor.
What I wonder is: how often does this actually happen -- that someone gets scooped? My guess is that it is very rare. Most new research moves the field forward a little at a time -- what chance is there that someone is doing exactly what you're doing?
If you've heard of this happening, please let me know, or respond to this posting.
In the meantime, my suggestion is that you should not worry about being scooped. The person who is doing similar research to yours will probably be a colleague someday, and you can co-author a paper. The most important thing is not to hide your work from others for fear of being scooped. I have found that those who fail to talk about their work with others have a much harder time finishing their dissertation, writing up their articles, and getting known in their fields. Let your light shine! OK, trite. But true.