Otdfbt

I believe there should be a line somewhere between suggesting / advising good practice and appearing pushy for implementation. You don't need to chase everyone, individually to make them follow the advise.

Your organization made enough attempts to make the employees aware of the danger and given them guidelines for safe posture. Now it's up to them to comply. They're not kids. The organization can, periodically keep the campaign running, in form of the usual

"[....] discussing in safety moment during meetings or by putting fliers in notice boards, [...]"

If someone wants to follow the bad and dangerous habits, that's their choice ^[1]. Nothing you try to do, most likely, will have any effect.

Oh, and please drop the idea of using the audio beep over the PA, it'll be hugely counter-productive, causing unnecessary distraction and annoyance.

[1]: Example: People smoke, despite the packets clearly showing "Smoking kills" and "Tobacco causes cancer".

We could inform my colleagues, during our monthly meeting, that they will be hearing a beep over the PA system. They could use this beep as an audio cue to re-align or adjust the posture.

Oh holy noodle.. that sounds truly awful.

Not only is it guaranteed to be annoy a large portion of the workforce it also wont be particularly effective. Assuming you have to do this "beep" reasonably frequently (because otherwise you're going to go so long between reminders that people will be spending hours in the "wrong" posture) then either people will succeed in effectively ignoring the "beep" (in which case it won't be prompting any action) or they won't be able to and it will be intensely irritating (there's a very good reason why the Annoy A Tron sold very well as a prank device!).

The use of a recurring beep to get people to do something is effective (think seat belt warning bongs in cars) but it's only effective because the beeping stops if they do what it wants. In your example you have no such feedback loop - everyone who is sitting in a good posture when the beep goes off is effectively being admonished to do what they are already doing and that's as irritating as all hell.

People tend to react strongly against:

1) Being spied upon and having transgressions alerted to everyone in the office

2) Being told how to live their lives

3) Being distracted when someone else in the team earns the "posture police" alarm tone (assuming they can hear it over their headphones)

4) People in the team who repeatedly and intentionally sets off the alarm and blames someone else

Companies are pretty good at ensuring that you have an ergonomically healthy working environment, but they have no obligation to make sure that you stay that way.

If you want to continue having good posture while working, that's great - but you can't expect to enforce the same in others.

Assuming your colleages are all grown-ups I find it quite ridiculous to have a posture police to make everyone sit straight. I bet they are all very aware of the damages bad posture can cause. It is up to them to decide what to do with that information.

And what's next? Enforce a healthy food policy and beep on people's ears when they have chocolate and soft drinks for lunch?

Worst. Idea. EVER.

First - Go to any site (or even google) advice how to keep focus at work. In most in the "worst" three there are audio cues. All advise to turn of outlook notifications, Skype/lynk/communicators "pings", generally block distractions.

Here you are adding distraction for everyone targeted at one person. At random time you take 15 minutes of "refocusing" from everyone because one person didn't sit straight. It take 7 minutes for person to change posture. So you can end up in people never really focusing on their jobs. Rather focusing on sitting straight to not hear that damn beep.

Second - having an irregular sound cue would lead to irritation (and could be classified as "hostile environment") in the work place. People like regular sounds. That's why 4/4 rhythm is popular while 7/11 is not.

Third - People tend to take the most comfortable position. Sliding under the desk is one of them. It's VERY ergonomic.

Best solution - buy chairs that help keep proper posture. Nice comfy chair don't mean it's good chair to work in. Club chair may be comfy to sit in but not for working.

If your employer is really so concerned about good posture...

...suggest that they buy different office chairs.

Fun fact: modern office chairs are specifically designed to have people to slide under the desk when they work (especially post lunch hours).

The pinnacle of office chair development seem to have been reached in the late 1970s or early 1980s. Office chairs have been developed that encourage (or rather enforce) a healthy posture while still being comfortable. "Enforce" seems to be a harsh word here, as it suggests that it goes against the user's free will, but it actually seemed to work by making the healthy posture so comfortable that everyone used it.

The downside? People regularly fell asleep in these chairs. You can still buy such chairs for your private use in your home office, but no reputable office supplier will sell any of these to any company which requires their employees to be awake during work hours.

Of course, you could use the PA system to wake up the employees (which now sleep in perfect posture) every ten minutes or so.

The previous sentence was a joke (I hope). The rest is not.