Designing Elder-Friendly Mobile Apps: Research‑Backed Typography Standards

Background and Motivation

Rapid economic and social development has led to a surge in older adults using mobile internet; users aged 50+ grew from 9.2% in 2015 to 26.3% in 2020. Despite this growth, seniors face many challenges when adopting mobile apps, making them a vulnerable group that requires focused attention.

National policies have begun to address these issues. In December 2020, the Ministry of Industry and Information Technology issued a special action plan for senior‑friendly and accessible internet applications. In March 2021, the 14th Five‑Year Plan emphasized accelerating information accessibility to help seniors and people with disabilities share digital life.

Research Goal

To support seniors, Baidu launched the "Large‑Font" and "Caring" versions of its apps in 2021. However, simply enlarging font size and line spacing does not guarantee better readability. Existing standards (e.g., WCAG 2.1) provide only broad recommendations that are too generic for mobile app design. This study aims to develop a concrete, evidence‑based design standard for text layout in news‑type/content‑type apps targeting older users.

Research Process and Methods

Defining Application Directions – The team mapped all text‑related pages and modules of news/content apps, identifying 12 usage scenarios. These were consolidated into four major reading contexts: three primary scenarios (long‑article reading, search, overview/feed reading) and one auxiliary information scenario. For the primary contexts, ideal font size, line height, and weight were investigated; for the auxiliary context, the minimum recognizable font size was determined.

Building an Evaluation System – Academic research on font size and line spacing was reviewed and combined with Baidu’s design experience. Four variables (font size, line height, weight, color) were selected as independent factors. Both subjective metrics (key‑information discovery, clarity, comfort, satisfaction) and objective eye‑tracking metrics (blink frequency, pupil‑diameter variability, reading speed) formed the assessment framework.

Experimental Procedure – Sixty participants aged 50‑70 were recruited. They performed tasks simulating real‑world long‑article reading, search, and feed browsing while wearing SMI‑ETG2w glasses for eye‑tracking. Questionnaires and interviews complemented the eye‑tracking data to evaluate the impact of different typographic settings.

Research Findings: Accessibility Design Standards

The analysis produced a complete, systematic set of senior‑friendly design standards for news/content apps, covering all page types and information hierarchies.

Ideal Font‑Size, Line‑Height, and Weight Combinations – For the overview (feed) and long‑article scenarios, the study specifies optimal combinations before and after optimization. (Images illustrating the before/after configurations are included in the original report.)

Minimum Recognizable Font Size – For black text (#1F1F1F), the smallest size that 75% of older users can read is 36 px.

Impact and Publication

The standards have been applied to Baidu’s Caring version and will be extended to the Large‑Font version and other senior‑focused apps. Baidu’s design team, together with the Aging Industry Association, published the "Mobile Internet Application Accessibility Design Requirements" as a group standard on 10 November 2021. The goal is to help the broader industry upgrade text layouts for older users and contribute to nationwide digital accessibility.