how accurate are these parsers? are they as accurate when they are measuring your own dps as they are measuring your team mates dps?

twice now i have been told that a tank is doing a higher dps than me, a dragoon. and although i am open to admiting that it is my fault, i dont think that it is. i have a good rotation cause i got it from theorycrafters, and my gear is good. it might be because us melee dps have to dodge so much where as tanks deal damage uninterrupted, but i have no way of proiving this.