Coding assessments at hiring events: leave with a decision, not a longlist

Coding assessments at hiring events only earn their keep when every candidate gets a real, scored technical conversation before the doors close. Most events don't manage that. A live 1:1 panel can't reach hundreds of people in a day, and a static test just pushes the real evaluation into weeks of follow-up rounds, so the better answer is an AI coding interview run inside the event window.

This piece is about career fairs, open hackathons, recruiting days for experienced engineers and staffing-agency hiring days. Campus placement drives are a different operation with their own calendar and constraints, and we've written about those separately in our guide to AI interviews for campus placement.

Key Takeaways

A hiring event should end with a decision, not a longlist. If the shortlist still needs four weeks of interviews, the event only did sourcing.
1:1 live coding doesn't fit an event. The interviewer-hours arithmetic breaks long before candidate number 200.
A static auto-graded test cuts the pool, but it tells you whether test cases passed, not how the candidate reasons.
An AI coding interview lets every candidate write code and then defend it, scored on one rubric, with a report card ready the same day.
Integrity is harder with hundreds of people in one hall and AI assistants a tab away. HackerRank's 2024 survey found 84% of talent acquisition professionals worried about AI-powered plagiarism.

What goes wrong with coding assessments at hiring events

The event itself is the easy part. You book the venue, the engineers show up, the badge scanner fills a spreadsheet. The trouble starts when you try to evaluate all of those people at the pace they arrived.

Look at how a large employer structures it. Cisco's Code with Cisco program runs a 90-minute online test of multiple-choice and coding questions under AI-based and video proctoring, sends about 75 finalists to a two-day in-person code-a-thon, then runs four virtual interview rounds before issuing a Letter of Intent within 7 days of final results.

That program is for students graduating in 2027, so it isn't the kind of event this piece is about. The shape is common everywhere, though: a test to cut the pool, an event, then a human interview queue behind it. The event narrowed the funnel. It didn't make the decision.

The failure modes repeat across formats:

The queue at the panel. Candidates are seen in the order they arrived, not the order of their ability, and some leave before their turn.
A pass or fail on test cases. The auto-grader knows the code ran. It doesn't know whether the person understands it.
The follow-up lag. Strong engineers at a hiring event are usually talking to other companies at the same event.
Scoring drift. Candidate number 12 meets a fresh interviewer at 10am. Candidate number 212 meets a tired one at 5pm.

Why 1:1 live coding does not fit an event

Live coding in a normal interview loop is a reasonable format, and plenty of good teams use it well. The problem is that it assumes one candidate, one interviewer and no clock pressing on either of them. An event breaks all three assumptions at once.

The first issue is signal. The Hiring Without Whiteboards list, a crowd-sourced directory of companies that skip whiteboard-style interviews, treats CS trivia, puzzles and brainteasers as bad interview practice and real-world problem discussion as the better format. An event floor is the loudest, most public setting for puzzle-under-observation interviews, with a queue of people watching over your shoulder.

The second issue is throughput. A human interviewer is a fixed number of hours, and each one of those hours covers a single candidate. The usual alternatives people suggest, such as take-homes and paid trial projects, assume days of candidate time, which is exactly what a one-day event doesn't have.

So the question for hackathon hiring and recruiting days isn't whether live coding is good or bad. It's how you keep the part that works (watching someone write code and explain it) without a human having to sit in every seat.

Why a static test at an event only moves the problem

Most teams answer the throughput problem with a static hiring event coding test. Candidates solve two or three problems, an auto-grader ranks them, and the top slice goes forward. It feels efficient on the day.

The cost shows up the following week. A ranking by passed test cases can't tell you who reasoned their way to a solution and who pasted one, so every shortlisted candidate still needs a human technical round. The interview load didn't disappear, it moved to the week after the event, when your engineers are back on sprint work.

We've covered the general case for static tests against live interviews in our piece on coding assessment software, so here we'll stay on event operations.

The interviewer-hours maths

Here's the arithmetic for a single recruiting day technical assessment, using round numbers you can swap for your own. Say 400 engineers register. A 45-minute live coding interview plus 15 minutes of write-up is one interviewer-hour per candidate, so a full panel needs 400 interviewer-hours.

Ten engineers staffing the booth for an eight-hour day give you 80 interviewer-hours. That covers one candidate in five, and which fifth you see is decided by who queued first. The remaining 320 hours land on the following weeks, which is eight engineers doing nothing else for a full working week.

This is the single-day version of the problem we describe in our guide to high-volume hiring. The fix isn't asking engineers to interview faster. It's moving their hours to the two places they matter most: agreeing the rubric before the event and reviewing the shortlist after it.

Running an AI coding interview inside the event window

An AI interviewer doesn't need an engineer in the seat, so candidates aren't waiting in line for one. Here's how the day runs when you set it up that way.

Before the event

Paste the job description and Expert Hire generates a rubric tuned to the role's seniority and stack. Your hiring manager edits the criteria until they match the bar, and calibration mode lets you run a known engineer through the interview and adjust the rubric until the score looks right. Then you upload your registrant list as a CSV and send the interview invites in bulk.

On the day

Candidates take the interview in their own browser with no install. It's a real-time voice conversation with a live coding environment, so they write and run actual code, and then the AI asks the follow-ups a good engineer would ask: why this data structure, what breaks at ten times the load, how would you test it. For senior roles, a whiteboard surface covers system design.

Every candidate is scored against the same rubric, whether they started at 9am or 4pm. If one of your booth engineers wants to hear a strong candidate in real time, Silent Listener (check which plans include it) lets a recruiter join a live AI interview as an observer and take over mid-conversation, then hand control back to the AI.

When each interview ends

The report card is generated automatically: a score per criterion, the code the candidate wrote, transcript excerpts and the AI's written reasoning for each score. We explain how those scores are built in how AI interviews are scored.

Structure is also where the research points. Schmidt and Hunter's 1998 meta-analysis put structured interview validity at .51. Sackett and colleagues revised that to roughly .42 in 2022 (Journal of Applied Psychology), with structured interviews still ahead of unstructured ones. Booth chats are unstructured by default, and our methodology page covers how the rubric is designed.

An event concentrates every integrity risk. Candidates sit next to each other, share the venue Wi-Fi and have an AI assistant one tab away. The HackerRank 2024 Developer Skills Report, a vendor survey of 4,107 respondents, found 84% of talent acquisition professionals concerned about AI-powered plagiarism.

The same report shows the disagreement you have to settle before the day. 47% of developers approve of using AI assistants in assessments, while half of recruiters disapprove and only 18% approve. Pick a policy, write it into the candidate briefing and score against it, because nothing sours a hackathon faster than a rule announced after the fact.

On the tooling side, the secure desktop proctoring app (check plan availability first) adds tab-switch awareness, screen monitoring and voice-consistency checks, and a Persona integration can verify identity before the interview begins. The stronger defence is the conversation itself. Someone who pasted a solution usually can't explain why it works when the AI asks, and that gap shows up in the transcript. There's more detail in our guide to detecting AI cheating in interviews.

A practical note for venues: a voice interview in a loud hall is hard work for everyone. Set aside a quieter area, ask candidates to bring headphones, and stagger start times so the room isn't at peak noise all at once.

The 72 hours after the event

Day 0, the evening of the event. Interviews finish, report cards exist, and Slack or Microsoft Teams alerts tell the team as each one completes. The shortlist exports to Greenhouse, Lever, Ashby or another supported ATS with the report card attached.

Day 1. Hiring managers read report cards for the top slice, not for all 400 registrants. Because each score carries the transcript and reasoning behind it, a manager can disagree with a specific criterion instead of re-interviewing from scratch.

Days 2 and 3. Final rounds go to people, where they belong, and final-round human interview mode puts a human interviewer in the seat with copilot-style hints surfaced in real time. Compare that with the four interview rounds that follow the Cisco code-a-thon. Part of what those rounds probe, technical capability in particular, is ground an AI interview at the event could already cover.

For staffing agencies running a hiring day across several client roles, each client can get its own rubric, and the report card can be embedded in the client-facing report. Everyone who didn't advance should hear back inside the same 72 hours, and where you enable it, candidates can see the criteria they were scored on.

Frequently asked questions

What's the best way to run a coding assessment at a career fair?

Don't make candidates queue for an engineer. For a coding assessment at career fair scale, send the interview link when they register or scan a badge, let them take an AI coding interview on their own laptop, and keep your engineers free to talk to the people whose report cards stand out.

Does hackathon hiring still need a coding assessment if we can see the project?

Usually, yes. A hackathon project shows what a team shipped in a weekend, not what each person understands, and one strong engineer can carry three others. A short individual interview where each person explains their part of the code separates contribution from attendance.

How long should a hiring event coding test be?

There's no universal number, and we'd be suspicious of anyone who gives you one. For reference, Cisco's program uses a 90-minute online test before its code-a-thon. Aim for one real problem plus enough follow-up conversation to hear how the candidate thinks, and keep it short enough to finish before the venue closes.

Can candidates use AI assistants during a recruiting day technical assessment?

That's your call, and developers and recruiters disagree sharply on it, per HackerRank's 2024 survey. Decide before the event, tell candidates in writing and build the rubric around the policy. A conversational interview helps either way, because the follow-up questions test whether the candidate understands the code in front of them.

Is this the same as a campus placement drive?

No. Campus drives run on a placement-cell calendar with a single graduating cohort, and they have their own playbook. This article covers open events like career fairs, hackathons and recruiting days for experienced engineers.

A hiring event should end with a decision

The point of pulling hundreds of engineers into one place is to decide something while they're still interested. A 1:1 panel can't reach them all and a static test defers the real evaluation, so the event quietly turns into a longlist and a month of follow-up rounds. Run the technical interview inside the event window, score everyone on one rubric and give your engineers the shortlist, not the queue.

If you want to see what that looks like, the Expert Hire AI interview platform page walks through the scored report card each candidate produces, with the transcript behind every score.

By TK, Growth at Expert Hire. Last updated September 29, 2026. Reviewed by Anand Suresh, CPO at Expert Hire.