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Pareto principle, or the 80:20 rule

The Pareto principle states that 80% of your work will be accomplished in 20% of the time, and 20% of your work will eat up the remaining 80% of your time.

The Pareto principle states that 80% of your work will be accomplished in 20% of the time, and 20% of your work will eat up the remaining 80% of your time.

One of the most frustrating truths of software development is that the complicated stuff, the making of the guts of a web app, are never what takes the longest. You can build a reasonably robust and functioning web app within a matter of days or a few short weeks.

What takes time is everything that comes after that, all of the refining, finessing, and testing that makes a functioning web app a professional, ready-for-the-public, web app.

Among themselves developers call this the 80:20 rule. 80% of the functionality of a web app will take 20% of the time to build, and the other 80% of the time will be spent on the remaining 20% of the functionality. It will be the small stuff–incremental refinements and last-minute optimizations–that will chew through your schedule and budget.

Turns out, this isn’t just a facet of software development, but a basic tenet of the human experience. This phenomenon is commonly referred to as the Pareto principle after the Italian economist, Vilfredo Pareto, who observed that in 1906 80% of the land in Italy was owned by 20% of the people. At it’s most simple, the Pareto principle says that in many different aspects of life you will find that “80% of the effects come from 20% of the causes.”

Sound bogus? Turns out there is a mathematical explanation.

The Pareto principle was made famous by Joseph M. Juran, a business and management consultant who was an early advocate for lean manufacturing and approaching business management with an eye for the nuances of human relationships.

In what aspect of your life, business or work do you see the Pareto principle play out? Tell us in the comments.

Cocktail Party Fact

Another common way that the Pareto principle plays out in business is the old adage that “80% of your revenue will come from 20% of your customers.”

It has also been observed that in gardens 80% of your peas will come from 20% of the pods. On construction sites 80% of injuries will be caused by 20% of the safety hazards. And unsurprisingly, in health care, 20% of patients will need 80% of the health care resources.

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  2. annie Replied

    also why do 80% of my pimples appear on 20% of my body???

  3. annie Replied

    I put together a book of my comics and it seems like 80% of the work is actually dealing with the pain in the neck website that publishes it, fussing with uploading, final design, etc. I thought it should be so easy because all my inside material was already finished and just had to be plugged in!!!

  4. NewEnglandNoir Replied

    Weddings! 80% of the friend-of-bride duties will be performed by 20% of the bridesmaids. :)

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