A cloze test uses a text with regularly deleted words (usually every fifth word) and requires the subjects to fill in the blanks. The percentage of words correctly entered is the cloze score. The lower the score, the more difficult the text. Because even advanced readers cannot correctly complete more than 65% of the deleted words correctly in a simple text, texts for assisted reading require a cloze score of 35% or more. Texts for unassisted reading need a higher score. Cloze scores line up with scores from multiple-choice tests in the following manner:

Purpose Cloze Multiple-Choice
Unassisted reading 50-60% 70-80%
Instructional, assisted reading 35-50% 50-60%
Frustration level Below 35% Below 50%
Table 7. Comparison of cloze and multiple-choice scores.

For the origins of these scores, see "Problem of Optimal Difficulty" below.

A cloze test uses a text with selected words deleted and replaced with underlines of the same length. Having at least 50 blanks in the reading selection increases the reliability of the test.

To score a cloze test, use the percentage of all the words that are correctly entered, that is, the right words in the right form (no synonyms), number, person, tense, voice, and mode. Do not count spelling.

It greatly increases the accuracy of the test to test all the words by using different versions of the text. If you delete every 5th word, there are five possible versions, each one with a different first deleted word. Divide the subjects into as many groups as you have versions and give each group a different version.

Here is a sample cloze test:

The potential for two-way _______ is very strong on ________ Web. As a result, ________ companies are focused on ________ Web's marketing potential. From ________ marketing point of view, ________ virtual worlds can attract ________curious Web explorers, and ________database engines can measure ________ track a visitor's every ________.

See the answers at the end of this article. Note that the standard cloze test does not provide the a list of the correct words to choose from as some online cloze programs do.

Cloze testing became the object of intensive research, with over a thousand studies published (Klare 1982). It quickly became popular as a research tool, and tended to complement not the formulas as expected but conventional reading tests. Unlike multiple-choice tests, cloze tests can provide suggestive information about individual sentences, clauses, phrases, and words. Cloze tests are suitable for intermediate and advanced readers. Cloze testing opened the way for much more intensive studies of the readability formulas, beginning with Bormuth in 1966 (see below).

Reading ability, prior knowledge, interest, and motivation

The interest factors affecting the readability of children's literature was taken up by Gates (1930) and Zeller (1941). One of the interest factors that Gates mentioned for children was reading ease. Flesch's early formula for adults (1949) included interest factors for measuring readability. The new research would establish that, along with vocabulary and sentence structure, the reader's reading ability, prior knowledge and motivation are powerful contributors to text readability.