The Hour You Gain Can Still Hurt Your Records

Early Sunday the clocks went back. Everyone says the same thing on Monday: “Nice, we got an hour.” Nobody asks the better question. Who wrote down what happened during the hour that happened twice?

Here is the part people get wrong. The injury scare is a spring story, not a fall story. A 2009 study in the Journal of Applied Psychology (Barnes and Wagner) looked at U.S. mining injury data from 1983 to 2006. On the Monday after clocks move forward, workers lost about 40 minutes of sleep, there were more injuries, and lost workdays went up nearly 68 percent. After the fall change, this study found no statistically significant change in sleep, injury count or severity. One occupation, one dataset, a link between sleep and injury. It is not a rule about your plant, and it does not tell us whether a site can untangle two log entries marked 1:30.

So do not post a scary poster. Look somewhere else. Look at the paper.

Picture a night shift lead. The clock hits 1:59, rolls to 1:00, and 1:30 shows up a second time. A pallet is moved at 1:30. A batch is checked at 1:30. A scale is verified at 1:30. Which 1:30? On Monday morning the day shift reads two entries with the same time and no way to tell which came first. If anything went wrong in that hour, you cannot rebuild the order of events. This is an example, not a story from a plant. The mistake it shows is real: we trust the timestamp because it always worked before.

The move. Before the next clock change in March, do three things.

1. Ask who keeps time records by hand or by system on your floor. Log books, check sheets, handoff notes, anything with a clock time on it.

2. Check your approved time-record rule. If local timestamps can repeat, agree on how the first and second 1:30 are told apart, such as the daylight or standard time label, or a UTC timestamp. Do not change old entries or invent a rule for controlled records. Take a missing rule to the person responsible for the record.

3. Say it out loud at the first shift after the change. One sentence: “Last night 1:30 happened twice. Here’s how we marked the first and second entries.” Then read one sheet the next morning. Can you put the hour in order?

Try this: open the overnight log from Oct 31 into Nov 1. If your area changes clocks, look at the entries from 1:00 to 2:00. Can you tell the two passes apart? If not, flag the gap to the record owner today, protect the original entries, and agree on a clear method for the next clock change. Spring’s missing hour needs a different check.

Source: Barnes, C. M., and Wagner, D. T. (2009), “Changing to daylight saving time cuts into sleep and increases workplace injuries,” Journal of Applied Psychology (APA summary).

Go deeper: Safety Is a Habit, Not a Warning and Team System Check.

Marc Bradburry
Big Bearded Ginger