ak for kind information: what is "same or similar' job?

Same job: the position to be under the same catergory in DOT code or O*NET classification.

well, how about similar job??
For example, if one works on the region of material engineering,
http://online.onetcenter.org/link/summary/17-2131.00
Could he works on the region of mechanical engineering,
http://online.onetcenter.org/link/summary/17-2141.00From the website, these two are Related Occupations.

Welcome any kind information and have a nice weekend.