Manually over-riding business rules, or dealing with the unexpected

15 July 2008

I was reading the other day about a curious incident on a plane flight that involved a problem with the airline’s business rules. A passenger had booked a seat for herself and her child, who would sit on her lap, as permitted by the airline’s rules. However, the airline refused to fly them as the child was a conjoined twin – it had two sets of lungs and therefore needed two air-supplies in case of emergencies and the aircraft did not have that spare capacity. Hence the business rule that had always been implied - one passenger would only ever require one emergency air-supply – was false.

When trying to model a business, it’s probable that you will miss some of the more obscure (and correspondingly less likely) business rules. This is not the “asteroid hit” tiny-probability/huge-impact scenario; there are a multitude of low-probability/low-impact scenarios that, while not necessarily life-threatening, could certainly spoil your customers’ day.

I was thinking about how to model this in a manner that did not give an unmanageable multitude of exception conditions. In engineering terms, the common best-practice is to allow for a “catch-all” exception:

  • In human-computer interaction modelling via scenarios or use-cases, make use of a default exception flow; when implemented in a system, this may be a work-queue for a supervisor to deal with manually.

  • In systems engineering and in real-time systems, there is a succession of fail-to-safe or “limp-home” modes; these can be imagined as concentric circles of smaller and smaller useable subsets of functionality, the smallest of which gives a “minimum stakeholder guarantee”, a small portion of functionality that is delivered if all else fails - perhaps an entry in a diagnostic log, or a handover to manual human control.

To return to the airline, the problem was having no available workaround to solve the business-rule impasse, to ensure that all parties were satisfied. In terms of day-to-day business planning, the best idea is to empower your workforce - by providing adequate resources and sufficient personal development - to have the flexibility and confidence to deal with these exceptions when they occur.

Success Stories

"Agilier's experience in managing business processes made them an ideal candidate to manage functional integration thereby reducing a significant risk to the business. This involved them working with the workstream leads and developing a high-level integrated businesses process against which we planned our programme."

Chris Davies
Programme Manager, EADS Defence and Communications Systems


"I was extremely happy with the professional and complete way that Agilier performed their work and would not hesitate to use their services again."

Mike Haynes
Senior Project Manager, Cogent Defence and Security Networks


Our latest writings, or thought-pieces, appear here.

Take a look at our free, time-saving templates in our new section.

Keep in touch with the latest ideas to help your organisation deliver. Click here for more.

RSS Feed