Editor’s note: This article is part of the series The Right Tool for the Job: Improving Reading and Writing in the Classroom that provides in-depth reviews of several promising digital tools for English language arts classrooms. This article and this series originally appeared on the Thomas B. Fordham Institute’s Common Core Watch Blog on October 13, 2016.

The use of text sets is a promising instructional approach that is informed by solid research on reading comprehension. A text set is a collection of texts that are tightly focused on a specific topic. As described in this earlier post, it may include varied genres and media and can be organized in many different ways. But all high-quality text sets have this in common: they are designed to build knowledge of an academic topic and are presented in a specific order with attention to text complexity, vocabulary development, and background knowledge.

However, quality text sets are difficult to find and not easy to create, so identifying resources that can assist is invaluable. Newsela, ReadWorks, and Achieve the Core are three sites that all provide particularly high-quality text sets for use in the classroom. I have reviewed each of them previously, and you can find those reviews here, here, and here.

All three sites offer useful text-set resources, but which best meets an educator’s needs? The table below summarizes some of the most important features and resources on each site.

Let’s discuss each row in turn.

1. All three sites offer access to Common Core–aligned, high-quality texts from a variety of sources. Newsela has relationships with well-known media organizations, such as The Washington Post, Scientific-American, The Los Angeles Times, and the Associated Press, and it posts many news articles daily. Newsela also uses primary-source documents and historical documents in its text sets. ReadWorks has commissioned authors to write many of its passages and has partnerships with organizations such as the National Audubon Society, History.com, and the American Museum of Natural History. Achieve the Core’s text sets have the greatest variability, incorporating a variety of published texts, including books, poems, articles, song lyrics, videos, and websites.

ReadWorks and Achieve the Core offer approximately forty text sets each. Newsela’s site contains more text sets but lacks some of the resources that the other two sites offer. For instance, ReadWorks provides vocabulary resources and questions specific to text sets, while Achieve the Core offers classroom activities specific to each text within a text set.

2. Achieve the Core is the only one of the three sites that purposely orders its text sets with regard to vocabulary development, text complexity, and the building of background knowledge. This is a key characteristic of effective text sets, and teachers should give it due attention. ReadWorks does provide general guidance relative to the reading skills being taught, but its paired passages and text sets are not ordered. Newsela does not provide suggestions or guidance with regard to text order.

3. Both Newsela and ReadWorks offer text-dependent reading-comprehension assessments. Newsela provides four multiple-choice questions and an optional short-answer question for each article. The majority of ReadWorks’ passages contain assessments. These vary in length but usually contain five to ten text-dependent multiple-choice and short-answer questions.

4. ReadWorks provides questions for its passage pairs and text sets. This is unique to ReadWorks and constitutes a strong feature because it requires students to integrate knowledge from more than one text.

5. Achieve the Core provides guidance on how to use text sets by providing Common Core–aligned activities for each text as well as additional resources such as graphic organizers. The other two sites provide general guidance on the use of text sets and even have a few sample lesson plans, but Achieve the Core’s activities and implementation guides are much more thorough.

6. Both Newsela and ReadWorks offer multiple versions of texts to meet the needs of struggling readers. ReadWorks offers more accessible versions of many passages (a feature called StepReads) but not all passages. Newsela does this best by providing each article at five distinct Lexile levels. The site also continually assesses a student’s reading performance and adjusts the article level assigned to each student accordingly.

When it comes to usability (not shown in the table), ReadWorks is the easiest of the three sites to navigate. Although all three are well designed, ReadWorks has a straightforward format and clear, easy-to-use search functions. A teacher can swiftly find paired passages at specific grade levels that are focused on specific topics or skills. The only drawback is that it is difficult to find the text sets on the ReadWorks site, as this site does not have its own search feature.

Individually and together, Newsela, ReadWorks, and Achieve the Core provide teachers with online text-set resources that can be integrated into any instructional program to help build vocabulary, background knowledge, and strengthen reading comprehension. I encourage you to visit these sites and try teaching with text sets. You will find both the strategy and the resources quite powerful.