Murphy's Law for Event Managers: How to Build an Event Contingency Plan for Everything That Can Go Wrong

Originally published March 2016. Updated October 2026.

Every organizer has a story about the projector that died five minutes before the keynote, or the wifi that collapsed just as the doors opened. Murphy's Law says this is not bad luck; it is the normal state of events. The useful response is not to hope for a smooth day but to write an event contingency plan that assumes several things will fail, and decides in advance what your team does when they do.

Where Murphy's Law and Stapp's Law came from

Murphy's Law is usually stated as "Anything that can go wrong, will go wrong." It is credited to Edward A. Murphy Jr., an engineer working on US Air Force rocket-sled deceleration experiments in the late 1940s. His job was testing experimental equipment, so things that did not go to plan were part of every week.

Stapp's Law comes from the same program. Colonel John Paul Stapp, the Air Force flight surgeon who rode those rocket sleds himself, is credited with the line: "The universal aptitude for ineptitude makes any human accomplishment an incredible miracle." In plain terms: people make mistakes, all of us, all the time, and getting anything complicated done is an achievement.

Both sayings were born in an environment where failure was expected and planned for. That is exactly the mindset an event needs.

What the two laws mean for an event organizer

You already know the everyday versions. You switch to the shorter checkout line and it immediately becomes the slowest. You search a page for a word, give up, and the person who asked points to it right in front of you. The obvious mistake is the one you cannot see.

At an event, the same patterns show up in predictable places:

• Murphy's Law covers the things: equipment, venues, networks, deliveries, weather and transport.
• Stapp's Law covers the people: a typo in the start time on the invitation, a volunteer who never got the briefing, two teammates who each assumed the other booked the caterer.

It does not matter whether you run a black-tie fundraiser or a neighborhood council meeting. The size of the event changes the size of the consequences, not the likelihood that something will slip.

Most event failures are not dramatic. They come from miscommunication, from backup plans that existed only in one person's head, and from a gap between what you pictured and what actually happened on the day. All of these can be planned for.

How to build an event contingency plan

The original advice on this blog still holds: assume each step of your plan will go wrong, picture how, and prepare a response for each. Here is that idea turned into a process you can run in an afternoon.

1. List every step of the event. Walk through it from the attendee's side: invitation, registration, confirmation email, travel, arrival, check-in, sessions, meals, sponsor areas, departure, follow-up. Then do the same from the team's side: setup, deliveries, AV checks, staff briefing, teardown.
2. For each step, ask "what if this fails?" Write down the two or three most likely failures. Be specific: "main-hall microphone stops working" is useful; "AV problems" is not.
3. Rate each failure. How likely is it, and how bad would it be? A lost lanyard box is likely and mildly annoying. A venue power cut is unlikely and serious. Spend your effort on the likely-and-serious corner first.
4. Write the response. For each risk, note the trigger (how you will know it has happened), the action, the backup resource and the person who owns it.
5. Decide what you will not do. Nichols' Fourth Law says, "Avoid any action with an unacceptable outcome." If an outdoor stage with no rain cover could end the event, the contingency is not a plan B; it is choosing a different plan A.
6. Share it, test it, update it. A contingency plan in one laptop folder fails the Stapp test. Everyone who has to act on it needs to have read it.

For the bigger risks — medical incidents, evacuations, severe weather — see our guides to emergency planning for conferences and event risk management.

The failures that show up at almost every event

You do not need to invent your risk list from scratch. These come up again and again.

Check-in: where Murphy is busiest

The front desk is where many of these failures collide: the wifi, the unexpected headcount and the human errors all show up in the queue at once. It also matters a lot to your attendees. In Bizzabo's 2025 State of Events report, 71% of attendees said ease of check-in could make or break their event experience, and 59% of organizers reported an increase in late registrations. Plan for a list that changes up to the last minute.

A few things to build into the check-in part of your plan:

• Assume the network will drop. WebMobi's QR check-in keeps scanning when the venue wifi dies and syncs the scans afterwards. The dashboard shows when each phone last synced and how many of its scans arrived late, so you know if a device may still be holding check-ins. More on offline event check-in.
• Have more scanners than you think you need. WebMobi's web check-in runs in any phone browser, so a volunteer's own phone can become a spare scanner if a device fails.
• Plan for people who never registered. With walk-in registration, staff add the person at the desk and check them in in one step, instead of sending them to a separate line.
• Keep a record. Every WebMobi check-in is logged: who was let in, by which staff member, on which device, and whether it was taken offline. When someone says "I was definitely checked in," you can find out.

Make the plan survive your own team

Stapp's Law is a reminder that the plan is only as good as the people carrying it out. The practical habits from the original post are still the right ones:

• Be detailed. Small problems are the ones nobody writes down. Note the door code, the loading-bay hours and the name of the venue's duty manager.
• Work to a timeline. A dated checklist makes gaps visible early, while there is still time to fix them.
• Get the team's sign-off. Walk your team through the plan and ask each person to find one thing that would break it. They will see the mistake that is "as plain as the nose on your face" to everyone but you.
• Give every task one owner and a deadline. "The team" does not own anything. A named person does, and so does their deputy.
• Limit who can send. Decide who approves attendee emails and agenda changes on the day, so corrections do not create new errors.

Software can take some of the human error out. In WebMobi, a new event sends no email until you turn its email switch on, so setting up an event can never mail anyone by accident. Every change to your event content is recorded — what changed, when and from where — and shown to the people who manage the event, which makes "who changed the start time?" a quick question to answer. If you need to change the event's web address, links to the old address still land on the event.

Rehearse, then review

A contingency plan you have never tested is a guess. Before the event, run a short tabletop exercise: read out a failure ("the main-hall screen is black and the keynote starts in four minutes") and have the owner talk through what they would do. You will find missing phone numbers and unclear handovers in minutes.

Rehearse the technology as well. In WebMobi you can publish an event in Test mode, run real registrations and scans through it with your staff, and none of them count. When you are ready, go live.

After the event, hold a 30-minute review while memories are fresh. What went wrong, which responses worked, what was missing from the plan? Add it to your template. Each event makes the next plan better, and Murphy has fewer surprises left.

If you want to rehearse your check-in and registration setup before your next event, you can create an event free on WebMobi and run it in Test mode first.

About WebMobi: before 2020, WebMobi’s event apps ran more than 2,000 events for over 2,000,000 attendees — among them the Boston Marathon, the Tribeca Film Festival, the NSW Department of Education and Connect ERA. More case studies.

Related on WebMobi: event check-in app

Frequently asked questions

What should an event contingency plan include?

A list of the likely failures for each stage of the event, how you will recognize each one, the action to take, the backup resource, and the named owner and deputy. Add key contacts (venue, suppliers, AV, medical) and where the plan is stored so everyone can reach it on the day.

How far in advance should I write the contingency plan?

Start it when you confirm the venue and main suppliers, because many backups (a second supplier, rain cover, extra power) need booking. Finish and share it at least a week or two before the event so there is time for a team walkthrough.

What is the most common thing that goes wrong at events?

It varies, but connectivity at the venue, late or changed registrations, AV problems and communication gaps inside the team come up at almost every event. Put those at the top of your plan and add event-specific risks after.

How do I keep check-in moving if the venue wifi fails?

Use a check-in tool that keeps scanning offline and syncs later, have a hotspot at the desk, bring spare devices, and keep a walk-in process for people who are not on the list. Brief staff on the offline procedure before the doors open, not during the problem.

Do small events need a contingency plan?

Yes, just a shorter one. Even a 30-person workshop can lose its room, its speaker or its projector. A one-page list of the five most likely failures and who handles each is enough.