The December Data Dip: How Holidays Reshape Evidence Generation

At Alethios, we believe context is part of science. Real-world evidence doesn’t live in a vacuum—it lives in routines, rhythms, disruptions, and the ordinary patterns of human life. And few moments disrupt those patterns more than the holiday season.

Whether a study is decentralized, in-clinic, or hybrid, the holidays bring a level of unpredictability that researchers everywhere have to account for.

On the Alethios platform, where participants contribute through daily tasks, wearables, and at-home activities, these seasonal shifts show up clearly. The key is understanding why—and preparing for it.

Seasonality Isn’t Noise—It’s Science

Evidence generation happens in the middle of real human lives. November and December bring changes to sleep, mood, routines, stress, diet, and movement that are so consistent they show up across population datasets year after year. Studies have long documented significant holiday-driven shifts in sleep duration, physical activity, and metabolic behaviors (Roberts et al., 2023).

These changes don’t reflect “poor” data or “noncompliant” participants—they reflect accurate behavioral science. But they can make it harder to separate the effect of an intervention from the effect of the season, especially in studies with short durations, daily tasks, or tightly timed protocols.

How Decentralized Models Account for the Holiday Effect

Seasonality affects every type of research, but decentralized models have built-in advantages for navigating it. Because Alethios studies happen in the real world—through wearables, at-home activities, and daily check-ins—we design protocols that anticipate seasonal disruption without sacrificing rigor.

Here’s how we account for the holiday effect:

1. Strategic study timing
We avoid scheduling critical moments (baseline weeks, product introductions, primary endpoints) during high-variability periods like late November and December. Starting studies well before the holidays gives participants time to stabilize their routines before seasonal changes begin.

2. Routine building early in the study
Participants who establish habits early are more likely to stay consistent during disruptions. Research shows that adherence improves significantly when routines are formed within the first 1–2 weeks of a digital study (Zhu et al., 2024). Early onboarding helps maintain quality even when schedules get chaotic.

3. A reminder system designed for real-life
Alethios uses timed nudges—push notifications, wearable sync reminders, and survey prompts—to reduce cognitive load when participants are busiest. These reminders preserve continuity without increasing burden.

4. Flexible contribution, structured endpoints
Decentralized models allow flexibility around noncritical tasks while keeping key endpoints tightly timed. This protects data interpretability even when participants are traveling or their schedules shift.

5. Date Specific Tasks When it Matters
Even in rolling study designs, decentralized models allow us to schedule time-anchored tasks on specific dates—like a check-in on Christmas Day or New Year’s Eve—to capture meaningful context right when it happens. We can also send multiple, well-timed reminders on those specific days, helping participants complete important tasks without increasing burden during an already busy season.

Designing with seasonality in mind makes decentralized research more resilient and more humane—acknowledging that evidence is generated by real people living real lives.

Simple Ways to Stay Engaged During the Holidays

Seasonal disruptions are natural — and expected. With a few small habits, participants can keep contributing smoothly even during busy holiday weeks:

• Set a routine early. Completing tasks at the same time each day before travel helps the habit stick.
  
  
• Keep notifications on. Reminders lighten the mental load when schedules get hectic. You can also set up push notifications, find out how here.
  
  
• Wear your wearable. Make sure your wearable stays on- even if it doesn’t go with your ugly Christmas sweater.
  
  
• Let us know if things change. Travel and routine shifts are normal — our team is here to help.
  
  

With small adjustments and a little awareness, participants can stay engaged while still enjoying the season—and help generate real-world evidence that reflects real life.

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Roberts, T. et al. “Seasonal and Holiday Variations in Sleep, Activity, and Metabolic Behavior.” Journal of Behavioral Health, 2023.

Zhu Y, Long Y, Wang H, Lee KP, Zhang L, Wang SJ. “Digital Behavior Change Intervention Designs for Habit Formation: Systematic Review.” J Med Internet Res. 2024;26:e54375