BPMN vs UML vs DFD – which one is best?

While many large companies still describe their requirements using the written word, there is a huge amount of evidence that pictures (i.e. modelling languages) are a clearer and more reliable method of communication.

A 2016 survey of Australian business analysts across 30 organisations (government, big business, SMEs) found that while 14% used one or more of the popular languages (DFD, UML, BPMN) regularly, the vast majority 76% did not or only very occasionally.

This shows that a small number of business analysts have found benefit in the use of modelling language but the majority still use plain English to try to describe business processes and systems. This may be because the modelling languages can seem intimidating – or more likely the analyst just hasn’t been shown how beneficial modelling languages can be.




The BABOK Guide® specifies that:

“One of the key objectives of business analysis is to ensure that requirements are visible to and understood by all stakeholders.”

While all business analysts want to deliver their projects to the best of their ability, many projects are still over-time and over-budget. Most often this is a result of poorly communicated or mis-interpreted business needs. How often have two people read the same piece of text and come to different conclusions? If you’re not making the requirements as visible as possible to stakeholders then you’re not doing your job.

Using a modelling language is nearly always the clearest way to communicate your understanding of an as-is system and demonstrate your recommendations for the to-be one. The language will also allow you to use layers – high level views to summarise the overall system and detailed views to clearly describe functionality.

Pictures in the form of modelling languages help get all stakeholders on the same page easily – and demonstrate concepts clearly without room for misinterpretation.

If you’re in an organisation that’s already using modelling languages we’d love to know which one you favour – leave us a comment below. If not, come along to our Business Analysis course and learn how to start making use of this powerful business analysis technique. You’ll also learn that each modelling language has different strengths and the skilled analyst knows what to use and when.

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