Hypothesis

Statement

Plain-language practices often improve accessibility, comprehension, or satisfaction, but their effect depends on audience, baseline, content, and outcome; they cannot serve as a universal communication objective.

Mechanism

Reducing unnecessary lexical and syntactic burden can free cognitive resources, but oversimplification can remove precision, and unchanged information structure or missing concepts can remain limiting.

Predictions

• Plain-language variants will show heterogeneous effects across source documents.
• Accessibility or satisfaction gains will not always imply comprehension gains.
• Audience expertise and the adequacy of underlying information will moderate effects.

Evidence that would support it

Controlled studies with heterogeneous effects, metric divergence, or cases where another representation outperforms plain wording.

Evidence that would contradict it

Broad, replicated evidence that a stable set of plain-language transformations improves all decision-relevant outcomes across audiences without meaningful tradeoffs.

Tests performed

Compared one randomized trial, one systematic review, and accessibility guidance.

Results

Supported at High confidence within written informational communication; broader cross-cultural and technical-domain testing remains.

Falsification attempts

The randomized trial showed a large comprehension benefit for one item, but a small nonsignificant benefit for another while satisfaction improved in both.

Current assessment

Plain language is a candidate intervention and accessibility constraint, not the project’s master theory.

Next experiment

Factor wording separately from information structure in a procedural task and measure both performance and subjective ease.