Readability and Content Quality

As a technical writer, you must communicate complex information clearly and effectively. The language used in documentation should be simple, unambiguous, and direct. This is crucial, as ambiguity, the use of complex jargon, or an excessive number of words can prevent documentation from fulfilling its primary function: to help someone understand the subject and perform a task. Ease of understanding should be a primary consideration. Only a high-quality text, written in an accessible way, can guarantee adequate results. An analysis of readability and content quality is invaluable in this context.

Key Metrics to Analyse for Readability and Quality

  • The Flesch-Kincaid Readability Score is a method of assessing how difficult it is to understand an English text. It consists of two tests: the Flesch Reading Ease and the Flesch-Kincaid Grade Level. Both tests use factors such as word length and sentence length to determine the difficulty of a passage.

    The Flesch Reading Ease test gives a score on a scale of 1–100. Higher scores indicate greater ease of reading. The test uses the following formula:

    206.835 - 1.015 * (words/sentences) - 84.6 * (syllables/words)

    The Flesch-Kincaid Grade Level test uses a US school grade level to assess the complexity of the text. The formula for this test is:

    0.39 * (words/sentences) + 11.8 * (syllables/words) - 15.59

  • The Gunning Fog Index measures the complexity of English text based on sentence length and word complexity. The score represents the years of formal education required to understand a passage on first reading. It is calculated using the following formula:

    0.4 * ((words/sentences) + 100 * (complex words/words))

  • Average Sentence Length (ASL) helps analyse the complexity of a document and its comprehension by the intended audience. The formula is straightforward: ASL is calculated by dividing the total number of words by the total number of sentences in a document:

    ASL = total words/total sentences

    The optimum number of words per sentence for clear technical writing varies. The general recommendation is to use between 10 and 25 words, according to various sources. More than 25 words per sentence is difficult to follow and should be avoided. The best practice is to break long sentences into smaller ones.

  • The Percentage of Passive Voice is also an important metric to consider, as excessive passive voice should be avoided. Active voice emphasises who is performing the action, and sentences tend to be shorter, making instructions easier to follow. The percentage of passive voice is easy to calculate:

    Passive Voice Percentage = (passive sentences/total senteces) * 100

  • Grammar and Syntax. As the aim of a technical writer is to produce clear and concise documentation, analysing grammar and syntax is an essential element of the technical writing process. Key benefits include improved coherence, elimination of ambiguity, consistency and accessibility. Professional documentation must be well written and conform to industry standards.

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