The Conversation That Started TallyFlex

How a simple idea from my BCBA wife led to building TallyFlex

My wife is a Board Certified Behavior Analyst. Five years ago, I’d watch her prep for sessions: three different colored tally counters in her pockets, two chronometers around her neck, a clipboard for notes. She’d come home exhausted, then spend another hour entering everything into her software.

One evening, we were talking about her workflow.

“It would be nice,” she said, “if there was just one dedicated device for data collection. Something that could handle everything without all this juggling.”

I’m a software engineer. That kind of problem—multiple tools doing what one should do—is the kind that gets stuck in my head.

The Arduino Prototype

The Arduino prototype: clunky, but it proved one device could handle multiple data types. Then I realized an app made more sense.

I started thinking about what that device would look like. At first, I went the hardware route—built an Arduino prototype with buttons and a small screen. It was clunky, but it proved the concept: one device, multiple data types, simple interface.

But the more I worked on it, the more I realized an app made more sense. More flexible. More maintainable. Accessible on devices practitioners already carry.

So I pivoted. But I had a problem: I didn’t understand ABA well enough to build something that actually worked for practitioners.

Learning the Field

I spent months studying. Watched product demos of existing tools. Read documentation. Talked with my wife about her workflows, her clients’ needs, the data structures that matter in ABA. She had ideas about what would make data collection easier—I worked to enhance those ideas with engineering.

What became clear: Applied Behavior Analysis depends entirely on accurate data. But the tools make good data collection surprisingly hard.

Practitioners were burning out trying to collect quality data while staying present with clients. The cognitive load of juggling multiple devices, remembering to record timestamps, switching between apps for different measurement types—it was exhausting. And that exhaustion led to incomplete data, which undermined the entire evidence-based approach ABA is built on.

This wasn’t just about temporal context or fancy visualizations. It was about making the fundamental task of data collection intuitive, efficient, and accurate.

Designing for One Thing Done Well

I started with a simple principle: what if everything happened on one screen?

• Count behaviors without switching tools
• Track duration without a separate timer
• Record ABC data without losing your place
• Capture timestamps automatically so patterns emerge naturally
• Work offline because wifi isn’t reliable in schools
• Sync in real-time so teams can collaborate

The first version was rough. Really rough. But my wife tried it during a session and came home with feedback I didn’t expect:

“I maintained eye contact with the client the whole time.”

That’s when I knew there was something here.

Making It Free

I made TallyFlex free. Not as a business strategy—I just wanted it to be a robust alternative for practitioners tired of expensive tools that didn’t work the way they worked.

Every behavior event captured with precise timestamps, revealing patterns within sessions that weekly aggregated graphs can’t show.

The School Story That Changed Everything

About a year in, a school reached out. They’d been using TallyFlex with a student who had severe disruptive behaviors. The teacher called to tell me they’d discovered something: every incident was clustering during transitions between 10 and 11am.

They adjusted the schedule—gave the student more transition time in that window. Within two weeks, incidents dropped by 60%.

“We would have taken a month to notice that with our old system,” she said. “We were just looking at weekly totals.”

That conversation changed how I think about this work. It’s not about making data collection slightly more convenient. It’s about giving practitioners the ability to see patterns that were always there but hidden—so they can respond faster when something’s not working.

What It Became

TallyFlex grew. Practitioners told colleagues. Schools adopted it. Clinics reached out. Today, it’s used by over 10,000 practitioners across ABA clinics, public schools, and private practices.

We eventually started charging after five years of free access. That was terrifying—would people actually pay for something they’d been getting for free? But they did. Many of the practitioners who’d been using it for years converted to paid plans and continue using it daily.

That told me we were solving a real problem.

What I Learned

Here’s what I’ve come to understand over the past five years: practitioners aren’t asking for better tools because they don’t realize better tools are possible. They’ve adapted their workflows so thoroughly that the limitations have become invisible—even to experts.

My wife didn’t wake up one day thinking “I wish my data had temporal context.” She woke up thinking “I need to figure out why this client’s behaviors are increasing.”

The temporal context problem only became visible when someone asked “why does it have to work that way?” Sometimes the outsider perspective helps—not because outsiders are smarter, but because they haven’t learned which problems to stop questioning.

Beyond ABA

While I built TallyFlex for ABA practitioners, I’ve watched the same patterns emerge across disciplines. Special educators tracking sensory regulation. Occupational therapists documenting fine motor progress. School psychologists measuring intervention effectiveness.

They all describe variations of the same frustration: “I know when things go well or badly, but my data doesn’t show me when or why.”

The tools were designed for different fields, but the problem is universal: practitioners supplementing aggregate data with memory because their tools only show totals, not temporal context.

Where This Is Going

There’s still so much to build, so much to learn. What works, what doesn’t, and what surprises me about how people use this tool in ways I never anticipated.

For now, I’m grateful to everyone who took a chance on something built by someone who started as an outsider to the field, but who believes that better data shouldn’t require more effort.

If you’ve ever felt that frustration—knowing something’s happening with a client but not being able to prove it with your data—I’d love to hear about it. That’s how this started, and that’s how it’ll keep getting better.

TallyFlex is an ABA data collection application designed for intuitive, efficient, and accurate data collection. Built with offline support and real-time collaboration so practitioners can focus on clients instead of tools. Learn more →