system
Given the following post, respond as if you're commenting on Reddit:
human
Found my masters dissertation was plagiarised. Where to go from here?

A PhD student from the lab where I did my masters 2 years ago submitted his/her thesis earlier this year, and as I was reading it, I noticed a number of similarities in the writing. I looked back at my dissertation and found a number of sentences and a whole paragraph from the literature review and the conclusions were either very similar or copied word-for-word. His/Her conclusions were drawn from mine because one whole chapter was a repeat of my masters work. Only two small parameters were changed: used Brand B instead of Brand A with the exact same specs and used a different arbitrary constant in the calculation. The end results were virtually identical, so it wasn't like their changes improved what I had done or built on top of the work in my dissertation; it was a repeat without the hurdles of optimising the parameters. Nowhere in the thesis was me or my work acknowledged or referenced.

I don't know what to do. On the one hand, I'm gutted that this happened. I am not confident in my writing at all, and I worked extremely hard to produce a good, coherent literature review and conclusions; I never even discussed my ideas with them, only my supervisor, who must have given them a copy of my dissertation. I knew my work would be in their thesis after I submitted my dissertation because our supervisor said he/she would use it (I learned all this after I graduated). Although I wasn't thrilled about it, I knew to expect it. On the other hand, in the worst case, this is two people's careers at stake, and as angry as I am, I don't believe my masters dissertation is worth two careers.

What would you do in this situation?
gpt
Don't ever let someone take credit for your work. A PhD is a title given to those who have earned it through hard work, dedication, and novel insights to their field. If they can't do their own lit review, they don't get a PhD. 

It's a disservice to you, your field and really that person. How long did it take to write that? How long does it take to copy someone else's ideas and words into a document? You deserve recognition for your work. 

Don't email the chair saying this was plagiarized. send both documents,, direct the chair to the plagiarized parts, say you've noticed many similarities and ask him to come to his own conclusions.