HTML data types in clinical trials
Why small form-design decisions matter even more when clinicians are documenting data during high-pressure ICU shifts
When you think about what makes or breaks a clinical trial, the first things that spring to mind might be recruitment, protocols, or data monitoring. But there’s something much quieter, often overlooked, that has a huge impact on data quality: the humble Case Report Form (CRF).
For teams using electronic CRFs (eCRFs), every field in the form is a chance to either capture data cleanly or invite errors. That’s where HTML input types — the behind-the-scenes choices made when designing a form — play a critical role.
At Spiral, we’ve seen how the right data type can save researchers hours of data cleaning and reduce frustration for clinicians entering information during a busy shift. It’s a small design detail that carries real-world consequences.
Everyday examples: when input types matter (especially in Critical Care settings)
Age or weight recorded as free text: One site types ‘65 years’, another just ‘65’, and another ‘sixty-five’. That’s three different values for the same thing. A number input type fixes this immediately, making sure the field only accepts digits.
Consent dates entered inconsistently: Without a date picker, you might see 03/07/25, 07/03/25, or July 3rd 2025 — depending on who’s typing. A date input type standardises it and reduces the risk of misinterpretation.
Yes/No questions offered as checkboxes: If both boxes get ticked, what does it mean? Radio buttons handle this cleanly by only allowing one choice.
These examples may sound small, but in the context of a multi-site trial with thousands of participants, they add up to significant risk for data quality, regulatory compliance, and ultimately, the reliability of study results.
Best practices for CRF input design in time-critical environments
Use native HTML types wherever possible: number, date, and email inputs come with built-in validation. They also adapt to devices — a number pad on a phone, a calendar picker for dates — reducing friction for site staff.
Be cautious with checkboxes: They’re great for multi-select lists like symptoms, but a poor fit for Yes/No.
Match the input to the question: Use dropdowns (select) for long lists, radio buttons for exclusive choices, and text areas for adverse event narratives.
Layer constraints for safety: Attributes like required, min, and max ensure the form protects against out-of-range or incomplete data before it’s ever submitted.
Why this matters for ICU trials
Clinical trials generate data that inform treatments, guidelines, and ultimately, patient lives. When input fields aren’t well designed, the burden falls back on research teams to chase missing data, resolve discrepancies, and spend time cleaning up issues that could have been prevented.
By making thoughtful choices about HTML input types, we’re not just improving a form — we’re supporting the integrity of the entire study. For trial teams working under pressure, that means more reliable data with less stress along the way.
A real-world example: ICU randomisation
In intensive care (ICU), speed matters as much as accuracy. In one of our ICU trials, we designed a screening and eligibility workflow with a very deliberate goal: minimise the time needed to randomise a patient.
Because ICU teams often work under extreme time pressure, every click and every field matters. We scrutinised the layout of our forms to ensure they were not just accurate, but also intuitive and quick to complete. The result was a workflow that allowed a patient to be screened, enrolled, and randomised in just a few minutes.
In contrast, the same workflow — when set up by another provider in a different region — took more than ten minutes to complete. That delay became critical during the height of the pandemic, when patients were arriving in rapid succession, and clinicians had no time to spare.
Ultimately, all the randomisation and enrolment tasks came to us because our fast, well-structured workflow could handle the pace. It’s a clear reminder that form design is not just a technical detail — it directly affects the feasibility of a trial and the ability of clinicians to deliver under pressure.
At Spiral, we believe that small design decisions have a big impact. HTML input types may not be glamorous, but when chosen well, they help ensure every trial runs a little smoother, and every dataset is a little cleaner. And in medical research, that makes all the difference.
Refer to examples: https://clinical-trial-crf-s-chxl.bolt.host/ (and click on HTML examples in the main navigation)
