Archive for January, 2010

StyleWriter’s Bog Index

January 19, 2010

 By Nirmaldasan


 “Editor Software’s plain English editing software, StyleWriter, has a new readability measure – the Bog index – so called because it measures how writing can bog down the reader,” writes Nick Wright, Director of Editor Software and co-designer of the StyleWriter editing software, in an article titled ‘Towards A Better Readability Measure  — The Bog Index’ in Pikestaff. It is available online at

 The computerized Bog Index has a graded 200,000-word dictionary and measures a number of variables. This formula is very unlike other formulae in that it adjusts its scores for 20 different writing tasks and three different audiences. Besides measuring sentence bog and word bog, it measures pep consisting of names, interest words, conversations and sentence variety. In short, Bog Index = Sentence Bog + Word Bog – Pep.

 Here follows Nirmaldasan’s (ND) interview with Nick Wright (NW):

 ND: What are the 20 writing tasks for which the Bog Index adjusts its scores?  

 NW:  General writing, academic paper, advertisement, fiction, instructions, legal document, letter, manual, memo, minutes, newsletter, newspaper, presentation, regulation, report, resume, speech, student essay, technical report and website.

 General writing is the default — but the formula adjusts for different writing styles by changing the weighting given to long sentences.  For example, the Bog Index gives more penalty for an advertisement or presentation written with the same average sentence length than a report or legal document.

 Just as important is the adjustment for audience where the user can select from: Public/inhouse/specialized.

 A public audience has no adjustment in the Index — but an in-house audience halves the penalty for using abbreviations and acronyms and a specialist audience halves the penalty for acronyms and abbreviations and technical words.

 ND: What is the scale of the Bog Index and how do we interpret the scores? 

 NW: The Bog Index changes depending on the audience and the writing task, but for general writing, the ratings are:

 0 to 20 = Excellent

21 to 40 = Good

41 to 70 = Average

71 to 100 = Poor

101 to 130 = Bad

131 to 1,000 = Dreadful

1000+ = Gobbledygook — Yes some legal writing consistently gets 1000+ scores.

 Just as important is the role of Pep — improving the readability of sentences.  There’s an explanation in the paper on readability.

 StyleWriter works out and displays the score and the rating for whatever audience or writing task chosen. 

 The best, most readable writing scores under 20.  Good magazines such as Time, Newsweek and the Economist score around 30.  Most business and government writing scores in the 60 to 100 range.

 ND: Don’t you think StyleWriter, with the help of the Bog Index, will compel people to write to a formula? 

 NW: No — the opposite. Most business and government writing uses a limited vocabulary and a predictable style of long sentences, passive verbs, nominalizations and wordy or clichéd phrases.  StyleWriter breaks these bad habits to allow clear English to flow through and the writer’s individual style to flourish.  If you put good authors through the StyleWriter program, it will highlight words, phrases and sentences to edit, but won’t change the underlying style.  J.K. Rowling still sounds like J.K. Rowling.

ND: Would like to know a bit about the members of your team who designed the Bog Index. 

NW: Our background is in research, journalism, plain English and editing.  I’ve run business writing courses for over 10,000 people.  Our programmer, Peter Stanton, who designed the mathematical formula is a former teacher and engineer. We’ve collectively over 60 years’ experience in writing and editing and software design.

Most of the analysis for the graded wordlist is easy and we have also used word frequency lists and sometimes even a Google search to see the familiarity of the word and graded them accordingly.  However, the proof of the index’s accuracy and usefulness is best measured by its use.  We’ve had several hundred users beta testing StyleWriter with the new Bog Index for the past five months.  Not one user has raised the issue of the way we have classified any words in our formula.

ND: Would StyleWriter incorporate other readability formulae such as the Fog Index?  

NW: Yes, it would be simple. But why? The Bog Index is so much more sophisticated than a simple word and syllable or character count.  Readability formulas are mostly 50 years old and are so basic as an editing tool as to be next to useless.  If they were any good, you could get them to highlight sentences above a certain level of complexity and suggest the writer edits them. Why has no one done this?  Because you would see at the sentence level just how poorly they analyze sentences. StyleWriter’s new Bog Index can do this and does — accurately picking out the ‘heavy’ sentences and showing how and where to edit them.

(For more details about StyleWriter and its Bog Index, check out or email