"Background knowledge plays a key role in students' reading comprehension. Our findings show that if students don't have sufficient related knowledge, they'll probably have difficulties in understanding text," said lead researcher Tenaha O'Reilly of Educational Testing Service Centre for Research on Human Capital in Education.
Previous research has shown that students who lack sufficient reading skills, including decoding and vocabulary, fare poorly relative to their peers. But the research of O'Reilly and ETS colleagues Zuowei Wang and John Sabatini suggests that a knowledge threshold may also be an essential component of reading comprehension.
The researchers examined data from 3,534 high-school students at 37 schools in the United States. The students completed a test that measured their background knowledge on ecosystems.
For the topical vocabulary section of the test, the students saw a list of 44 words and had to decide which were related to the topic of ecosystems. They also completed a multiple-choice section that was designed to measure their factual knowledge.
The results revealed that a background-knowledge score of about 33.5, or about 59 per cent correct, functioned as a performance threshold. Below this score, background knowledge and comprehension were not noticeably correlated above the threshold score, students' comprehension appeared to increase as their background knowledge increased.
The researchers plan to explore whether a similar kind of knowledge threshold emerges in other topic areas and domains.