APA has released the Sixth Edition of the "Publication Manual of the American Psychological Association," the guide social scientists have relied on since 1929. The new edition addresses the major changes in the publication world since the manual was last updated in 2001.

"There have been a lot of changes, many of them technology-driven and quite a few based on changes in the standards and expectations that go into scientific reporting," says Mark Appelbaum, PhD, a psychology professor at the University of California, San Diego, who chaired the revision task force.

As examples of technology-driven changes, the new manual now guides authors who want to post supplemental materials online such as videos, datasets and computer programs, additions that can give readers a more in-depth understanding of a study. The new manual also guides scientists on how to clearly present biologically based data, an essential update given the growing use of fMRI, EEG and other such techniques.

Changes in reporting standards are now reflected in the manual, which gives authors explicit instructions about the level of detail to go into when they report their results. Scientists reporting on findings from a randomized clinical trial, for example, are expected to state how many participants they started out with, the number of people who were eliminated from the study and the number of people who dropped out, among other things.

Also, the manual now emphasizes the reporting of confidence intervals and effect sizes, reflecting scientists' increasing use of statistical procedures beyond simple statistical significance testing.

Many of the manual's sections have been extensively rewritten, such as the materials on the graphical presentation of data through tables, figures and charts. "The last edition of the manual was pretty much based upon procedures that were in place when we submitted our figures as ... glossy prints," Appelbaum notes. "Today we live in the world of word processing and electronic submission."

Interestingly, given all the additions, the APA Publication Manual has shrunk from 439 pages to 296, says Mary Lynn Skutley, the editorial director of APA Books. That's because the book took its own advice and now provides a wealth of supplemental material online, such as tables of statistical abbreviations and directions specific to publishing in APA journals.

"We now speak to a broader publishing community," she says.

The style guide revision took more than three years and tapped hundreds of experts in fields including psychology, nursing, business, education and history, says Gary R. VandenBos, PhD, APA's publisher. The result is a reference tool that offers researchers "rules for clear communication, allowing us to focus our intellectual energy on the substance of our research," he says.

In addition to the revamped Publication Manual and related books, APA is rolling out a new APA Style Web site  to help people learn the style revisions through a free tutorial. Those seeking more in-depth knowledge of APA Style can take an online course for CE credit or visit APA's new Style Blog.

"The blog," says Skutley, "will give writing and style experts a place to talk about the tools of clear communication, and it will also allow us to hear from users."

To learn more about APA style, visit www.apastyle.org.