First author or last author: which position matters more?
In life sciences and medicine, both matter but signal different things. First author = the person who did most of the practical work, often a PhD student or postdoc, whose career gets the strongest boost from the paper. Last author = the senior researcher, principal investigator, or lab head who conceived and supervised. In mathematics, economics, and some physics, order is alphabetical and neither position has special meaning.
En détail
What first authorship signals
'This person did the work.' First-authored publications are the primary credential for PhD graduates and early-career researchers. In job applications and grant reviews, hiring committees often count only first-authored papers when assessing productivity.
What last authorship signals
'This person led the research group and funded the work.' Last authorship is often required for promotion to associate professor or full professor in life sciences. It signals independence — you now direct your own research program.
What middle authorship signals
Contribution but not leadership. Middle authorship helps but is usually weighted less by hiring committees. In interdisciplinary work with 10+ authors, middle positions may represent significant technical contribution — check the CRediT statement if included.
Field-specific variations
The first/last convention is strongest in molecular biology, biomedicine, and neuroscience. Chemistry and physics use it selectively. Mathematics and economics reject it entirely for alphabetical listing. Never assume the same rule across disciplines.
The corresponding author role is separate
The corresponding author handles communication and may or may not be first, last, or middle. Do not confuse corresponding with senior.