ARTICLE
Texts That Work: Specialized Guidelines for SMS-Based Legal Services
By Karen Heredia and Laura S. Quinn
Published: May 16th, 2025
Text messaging is a critical channel for reaching people with limited internet access, especially those seeking legal assistance. For many vulnerable populations—including those with limited data plans, irregular computer access, or unstable housing—SMS may be the most reliable way to maintain communication throughout a legal process.
What makes SMS particularly powerful for legal services is its ability to provide timely behavioral support. Research from court reminder systems shows that well-crafted SMS messages can increase court appearance rates by up to 26%, with even greater impacts for historically marginalized populations.
While text messaging offers unique advantages for reaching people in need of legal help, evaluating these systems requires specialized tools and approaches different from traditional website assessments.
A useful method to evaluate text-message-based processes is to assess them against established usability guidelines, known as heuristics. Until now, heuristics for evaluating SMS-based legal services simply didn't exist. Organizations have had to rely on general communication best practices.
This significant gap prompted our team to develop the first SMS heuristics framework specifically for legal aid services, as part of a collaboration with Legal Aid Chicago and Illinois Legal Aid Online (ILAO). We used these specialized heuristics to evaluate their innovative SMS services that guide their users through complex legal processes and ensure they don't miss critical deadlines.
Why standard digital heuristics fall short for SMS
Standard website heuristics fail to take into account how website vs. SMS interactions differ:
🌐 WEBSITE: User controls timing
📱 SMS: System controls timing
🌐 WEBSITE: Context visible on page
📱 SMS: Context must be maintained across time
🌐 WEBSITE: Visual hierarchy possible
📱 SMS: Limited formatting options
🌐 WEBSITE: Error recovery is immediate
📱 SMS: Errors can derail entire sequences
🌐 WEBSITE: Unlimited space for content
📱 SMS: Character limits constrain messages
Our heuristics framework incorporates best practices and behavioral science principles primarily from academic research papers, focusing on how text messages can:
Reduce friction for taking important actions
Mitigate psychological barriers like anxiety or avoidance
Provide just-in-time information when it's most actionable
Create accountability without triggering defensiveness
How to conduct a heuristic evaluation of your SMS system
The most effective way to use these heuristics is through scenario-based evaluation:
Start with realistic user scenarios. Don't just test random message sequences. Create specific scenarios like "Delia just got served eviction papers and is texting for help at 9 PM on her flip phone" or "Carlos is juggling three jobs and needs court reminders he can act on quickly during his lunch break." These scenarios keep you focused on actual user needs rather than theoretical problems.
Be systematic about coverage. Identify your key user groups, their main legal needs, and the devices they're likely using. For a complex SMS system, create 10-15 scenarios that collectively represent your primary audiences, major legal processes, and different technology contexts. You don't need every possible combination—just ensure each user type, legal scenario, and device constraint appears in multiple test scenarios.
Evaluate each pathway: Step through each scenario considering the eight heuristic categories below.
Document issues: Record where the experience fails to meet the heuristic standards.
Prioritize improvements: Focus on addressing critical barriers first.
Don't be discouraged when you find dozens (and dozens) of potential problems—that's normal and valuable. The key is prioritizing ruthlessly based on user impact and legal consequences. A confusing court reminder sequence might be more critical than inconsistent tone across informational messages.
SMS quick checks
If you're not ready for a comprehensive evaluation, you can take immediate steps to improve your SMS communications:
Audit your timing patterns, and whether the user has enough grounding information—look for messages sent after long gaps without context
Ensure your system accepts various ways users might respond (e.g., both "Y" and "YES" should work) across all your message flows
Identify critical legal requirements that might need greater emphasis
Test your error handling by intentionally entering unexpected responses (like "maybe" when expecting "yes/no") to see if your system recovers gracefully or leaves users stranded.
These quick assessments can identify your most urgent opportunities for improvement.
The Heuristics
The SMS heuristics at a glance:
Design Clear and Usable Messages
Time Messages Thoughtfully
Support Positive Behavior Change
Provide Clear System Feedback
Protect Privacy & Security
Ensure Accessibility & Inclusion
Create Clear Message Flows
Apply Behavioral Science Principles
Each section below contains:
A category heading that describes the area of focus
A brief description of what we're evaluating in this category
Specific heuristics to check during evaluation
1. Design Clear and Usable Messages
Ensure messages are easy to understand and respond to, minimizing user effort and confusion
Accept both short (like "YES") and complete responses
Be forgiving with spelling mistakes and typos
Make response options obvious and simple
Keep required user actions clear and straightforward
Write messages that clearly state what action is needed
Include personal details when relevant (like appointment times)
Make messages engaging without being pushy
Use a tone consistent with ILAO style
Break down complex tasks into smaller, manageable steps
2. Time Messages Thoughtfully
Send messages at appropriate times and frequencies to maintain engagement without overwhelming users
Message Frequency & Patterns (if spacing SMS over time)
Adjust how often messages are sent based on user needs.
Vary contact patterns to maintain engagement
Avoid predictable patterns that users might start to ignore
Mix informational messages with action-required messages
Alternate between different types of engagement (reminders, updates, check-ins)
Time messages for when users are most likely to act
Send action-required messages during business hours when people can respond
Avoid sending messages at disruptive times (very early morning, late night)
Response Handling
Send clear confirmations when users respond
Adjust future messages based on user engagement
Build engagement gradually over time: Start with simple, low-stakes interactions (like "Reply YES to confirm") and gradually introduce more complex interactions
3. Support Positive Behavior Change
Use proven behavioral insights to encourage positive action and engagement
Use conversational language that encourages interaction
Users understand where they are in a multi-step process
Support users in planning their next steps
Clearly explain consequences of actions/inactions
Highlight positive outcomes and progress
Use social proof (e.g., "Most people complete this step within 2 days")
Avoid overuse of loss aversion language (e.g., "Don't miss this important deadline because this will happen...")
Celebrate small wins and progress
Provide immediate positive reinforcement for actions taken
Offer solutions to common obstacles
Help users set achievable goals
Give constructive feedback on progress
4. Provide Clear System Feedback
Keep users informed about what's happening and what they need to do next
Confirm when actions are completed
Make next steps obvious
Give clear instructions to prevent mistakes
Provide easy ways to fix errors
Make help readily available
5. Protect Privacy & Security
Handle sensitive information appropriately and give users control over their data
Be careful of the details that might be seen in message previews
Do not request or send sensitive information
Be transparent about how information is used
Users understand how to opt-out/stop receiving recurring messages
6. Ensure Accessibility & Inclusion
Make the service usable for all users regardless of language, ability, or technology
Use simple, clear, and plain language
Provide service in multiple languages
Work with basic text messaging features:
Keep messages purely text-based
Use simple response mechanisms (like "Reply YES" or "Reply 1")
Break longer messages into clear numbered sequences if needed
Provide alternative methods for tasks requiring web access
Always include basic phone number alternatives
Minimize links that require data usage
Keep messages brief to avoid carrier splitting/fees
Being mindful of message frequency for users with limited text plans
7. Create Clear Message Flows
Design message sequences that are easy to follow and complete
Order messages in a logical sequence
Make it easy to go back to previous steps
Let users pause and resume conversations easily
Handle situations where someone has multiple issues
Disclose that user need to use different devices/phone numbers, if handling multiple legal issues
Provide clear summaries of important information
Sources
Suffoletto, B. (2016). Text Message Behavioral Interventions: From Here to Where?
Cooke, B., et al. (2018). Text Message Reminders Decreased Failure to Appear in Court
Nielsen, J. (2001). Deferred Hypertext: The Virtues of Delayed Gratification
Peevers, G., et al. (2008). A usability comparison of three alternative message formats for an SMS banking service
Material.io. Android Notifications
Szerovay, K. (2024). How to design better notifications
The Behavioral Insights Team (2014). EAST: Four Simple Ways to Apply Behavioural Insights
Schneider, C., Weinmann, M., & vom Brocke, J. (2018). Digital nudging: guiding online user choices through interface design