Whenever you include a paraphrase, summary, or direct quotation of another writer’s work in your paper, prepare your readers for it with a signal phrase. A signal phrase usually names the author of the source, gives the publication year in parentheses, and often provides some context. It is generally acceptable in APA style to call authors by their last name only, even on a first mention. If your paper refers to two authors with the same last name, use initials as well.
When you write a signal phrase, choose a verb that is appropriate for the way you are using the source (see 58c). Are you providing background, explaining a concept, supporting a claim, lending authority, or refuting an argument? See the chart at the bottom of the page for a list of verbs commonly used in signal phrases. Note that APA requires using verbs in the past tense or present perfect tense (explained or has explained) to introduce source material. Use the present tense only for discussing the applications or effects of your own results (the data suggest) or knowledge that has been clearly established (researchers agree).
Marking boundaries
Readers need to move from your words to the words of a source without feeling a jolt. Avoid dropping direct quotations into your text without warning. Instead, provide clear signal phrases, including at least the author’s name and the year of publication. Signal phrases mark the boundaries between source material and your own words; they can also tell readers why a source is worth quoting. (The signal phrase is highlighted in the second example.)
dropped quotation
Obesity was once considered in a very different light. “For many years, obesity was approached as if it were either a moral failing or evidence of underlying psychopathology” (Yanovski & Yanovski, 2002, p. 592).
quotation with signal phrase
Obesity was once considered in a very different light. As researchersYanovski and Yanovski (2002) have explained, obesity was widely thought of as “either a moral failing or evidence of underlying psychopathology” (p. 592).
Using signal phrases with summaries and paraphrases
As with quotations, you should introduce most summaries and paraphrases with a signal phrase that mentions the author and the year and places the material in the context of your own writing. Readers will then understand where the summary or paraphrase begins.
Without the signal phrase (highlighted) in the following example, readers might think that only the last sentence is being cited, when in fact the whole paragraph is based on the source.
Carmona (2004) advised a Senate subcommittee that the problem of childhood obesity is dire and that the skyrocketing statistics—which put the child obesity rate at 15%—are cause for alarm. More than nine million children, double the number in the early 1980s, are classified as obese. Carmona warned that obesity can cause myriad physical problems that only worsen as children grow older.
There are times, however, when a summary or a paraphrase does not require a signal phrase naming the author. When the context makes clear where the cited material begins, you may omit the signal phrase and include the author’s name and the year in parentheses.
Integrating statistics and other facts
When you are citing a statistic or another specific fact, a signal phrase is often not necessary. In most cases, readers will understand that the citation refers to the statistic or fact (not the whole paragraph).
In purely financial terms, the drugs cost more than $3 a day on average (Duenwald, 2004).
There is nothing wrong, however, with using a signal phrase to introduce a statistic or another fact.
Putting source material in context
Readers should not have to guess why source material appears in your paper. If you use another writer’s words, you must explain how they relate to your point. In other words, you must put the source in context. It’s a good idea to embed a quotation between sentences of your own. In addition to introducing it with a signal phrase, follow the quotation with interpretive comments that link it to your paper’s argument. (See also 60c.)
quotation with effective context
A report by the Henry J. Kaiser Family Foundation (2004) outlined trends that may have contributed to the childhood obesity crisis, including food advertising for children as well as
a reduction in physical education classes . . . , an increase in the availability of sodas and snacks in public schools, the growth in the number of fast-food outlets . . . , and the increasing number of highly processed high-calorie and high-fat grocery products. (p. 1)
Addressing each of these areas requires more than a doctor armed with a prescription pad; it requires a broad mobilization not just of doctors and concerned parents but of educators, food industry executives, advertisers, and media representatives.
To avoid monotony, try to vary both the language and the placement of your signal phrases.
Model signal phrases
In the words of Carmona (2004), “. . .”
As Yanovski and Yanovski (2002) have noted, “. . .”
Hoppin and Taveras (2004), medical researchers, pointed out that “. . .”
“. . . ,” claimed Critser (2003).
“. . . ,” wrote Duenwald (2004), “. . .”
Researchers McDuffie et al. (2003) have offered a compelling argument for this view: “. . .”
Hilts (2002) answered objections with the following analysis: “. . .”
Verbs in signal phrases
| admitted | contended | reasoned |
| agreed | declared | refuted |
| argued | denied | rejected |
| asserted | emphasized | reported |
| believed | insisted | responded |
| claimed | noted | suggested |
| compared | observed | thought |
| confirmed | pointed out | wrote |