Abstract
As research teams have grown larger, authorship lists of resulting publications have become longer. Organizations and journals have issued statements about ethical authorship, nature of contribution, and author responsibility, but author order is less frequently addressed. Unless the contribution of a co-author is specified, readers make their own assumptions about author contributions because practices on author order in the byline vary by discipline, journal, editor, publisher, scientific society, institution, country, and the authors themselves. Because contributions are often subject to misinterpretation and publications have become proof of scientific productivity and impact, it is increasingly important that authors themselves specify to readers the type and extent of contribution made by each author.