Do smoke alarms save lives?

Question

Almost all fire safety organizations and codes require the use of smoke alarms in new business and residential construction. The idea is that they save lives, as mentioned in this article from FEMA.

This article from Freakanomics calls into question their actual efficacy in saving lives, compared to other trends which have reduced fire deaths.

If the ionization smoke alarm was responsible for most of the decrease in fire deaths in the last part of the 20th century, shouldn’t the rate of decrease have been greatest over the time period that smoke alarm usage increased the fastest? Yet over the time period of 1977–1987, when the use of smoke alarms skyrocketed, the trend line remained relatively constant. The death rate was trending down before smoke alarms and continued to trend down after they saturated the market. It does not appear that ionization smoke alarms affected the trend line. NIST inexplicably ignores the trends in better building codes, reduction in smoking, better firefighting equipment, and better emergency medical care as likely reasons for the reduction in fire deaths.

Is there actual credible evidence that fire alarms reduce deaths from fire? Is all of the time and effort going into installing, maintaining, and dealing with the false alarms when they are set off by cooking just safety theater?

Answer 1

The argument from the Freakonomics article is somewhat problematic. It seems to boil down to the idea that, given that other things such as building code changes must have improved in ways that prevent fire deaths since smoke alarms were widely adopted, shouldn't the rate of deaths have plummeted instead of continuing the existing downward trend?

The first problem here is that he presumes building codes and such actually improved fire safety. If they somehow made things worse, and smoke alarms made them better, the trend would be more gradual.

Also, if you look closely at the death-by-fire graph, there are some interesting things to note. In the forties there was a substantial drop, which could be attributed to a significant portion of the population being off fighting a war, followed by them coming back from war and being available to fight fires. More importantly, there was apparently no substantial improvement in the death rate in the twenty years (starting around 1950) prior to the common use of smoke detectors; the line is essentially flat. Relative to THAT period, the later years represent a substantial improvement.

These figures, also from FEMA, strongly suggest fire alarms are worth the hassle:

Smoke alarms are still missing in 4% of U.S. homes. This group accounts for 39% of reported home fires and nearly half of all the reported home fire deaths. They represent just over 4 million housing units.

This indicates homes without alarms were far more likely to catch fire, or the fires were much less likely to get caught by the occupants early enough to be put out by the people making the discovery. In either case, detector-less homes were substantially more likely to have reportable fires, and they account for an outsized percentage of the deaths in question. Also:

Home fire deaths have declined substantially since the years before widespread home smoke alarm use. In 1977, when 22% of homes had smoke alarms, there were 5,865 home fire deaths. In 2003, when 95+% of homes had smoke alarms, the death toll had declined by 46% to 3,145. The home fire death rate, relative to resident population, declined by 59% in the same period.

Looking at these statistics, it's blazingly obvious (sorry) that you'd be taking a substantial risk not having working smoke detectors in your house.