Surface errors—grammar, punctuation, word choice, and other small-scale matters—don’t always disturb readers. Whether your instructor marks an error in any particular assignment will depend on personal judgments about how serious and distracting it is and about what you should be focusing on in the draft. In addition, not all surface errors are consistently viewed as errors: some of the patterns identified in the research for this book are considered errors by some instructors but as stylistic options by others. Such differing opinions don’t mean that there is no such thing as correctness in writing—only that correctness always depends on some context, on whether the choices a writer makes seem appropriate to readers.

Research for this book reveals a number of changes that have occurred in student writing over the past twenty-plus years. First, writing assignments in first-year composition classes now focus less on personal narrative and much more on research essays and argument. As a result, students are now writing longer essays than they did twenty years ago and working much more often with sources, both print and digital. Thus it’s no surprise that students today are struggling with the conventions for using and citing sources, a problem that did not show up in most earlier studies of student writing.

What else has changed? For starters, wrong-word errors are by far the most common errors among first-year student writers today. Twenty years ago, spelling errors were most common by a factor of more than three to one. The use of spell checkers has reduced the number of spelling errors in student writing—but spell checkers’ suggestions may also be responsible for some (or many) of the wrong words students are using.

All writers want to be considered competent and careful. You know that your readers judge you by your control of the conventions you have agreed to use, even if the conventions change from time to time. To help you in producing writing that is conventionally correct, you should become familiar with the twenty most common error patterns among U.S. college students today, listed here in order of frequency. A brief explanation and examples of each error are provided in the following sections, and each error pattern is cross-referenced to other places in this book where you can find more detailed information and additional examples.