Keying Errors

Keying errors. It refers to accidentally entering wrong or incomplete data on computer screens. Tim Harford’s post on the topic was triggered by a fine at a parking lot where he hadn’t entered the entire license number of his car. The system compared the parked car’s license plate number against the partially entered license number and concluded the car was parked without payment.

 

Harford discovered other cases where the cost and consequences of such mis-entries have been huge. In May, ‘24, a Citigroup trader’s mis-entry caused “fleetingly crash stock markets across Europe”. His error?

“The trader typed a number into the wrong box, asking the system to sell 58 million units instead of $58mn worth of units.”

Each unit was worth thousands of dollars, so the deal size ended up being billions of dollars instead of the intended $58 million.

 

We instinctively feel warning message would help. Since I work in Healthcare, I know the problem with warnings – after a point, doctors see so many warnings that they ignore them. It’s called “alarm fatigue”.

 

Another such user error in Citigroup “accidentally transferred $900mn of its own money to some creditors of Revlon, the cosmetics firm”!

“Some of those creditors decided to keep the money, on the grounds that Revlon did indeed owe it to them.”

 

The most tragic consequence though was from the 1980’s of Therac-25, “a radiation-therapy device in the 1980s that could fire high-energy beams either of electrons or X-rays into patients”. The mode mattered – with X-rays, a “flattener” was used by the machine to block a lot of the radiation, thus preventing high doses on the patient.

“The operator entered an “e” for the electron beam, then realised she had meant to type “x” for the X-ray, and swiftly moved the cursor back to correct the entry.”

Too late. There was a bug in the system – when the setting was changed too quickly (as in this case), the system ignored it because it had already initiated the hardware setting changes based on the original entry.

“The X-ray beam was fired without the flattener, delivering an extreme dose of radiation.”

It proved fatal. The patient died soon from the over-dosage induced complications.

 

While there is no foolproof solution, I am happy that the UPI apps (at least PayTM and PhonePe) do their bit to prevent transferring amounts by mis-entering. The amount is shown on multiple screens – once where you enter the value, and then again in the password entry screen as a reminder.