Progressive disclosure hides subordinate information until someone deliberately asks for it, and it shows up across nearly every navigation pattern, drop-downs revealing subordinate links beneath a horizontal bar item, accordions expanding a section of a vertical menu, tree views opening one level of a hierarchy at a time. Small visual cues do the signaling: carets or triangles, plus and minus signs, right-pointing arrows that rotate or change once expanded.
What makes progressive disclosure work is consistency, the same visual cue needs to mean the same thing everywhere it appears. A caret that expands one section but functions as a plain decorative icon somewhere else teaches people the wrong lesson about how to interact with it.
Progressive disclosure isn't one technique used the same way everywhere: it's a principle applied differently depending on what's being hidden and why, and each application needs to be judged on its own terms.
1: Appropriate. A drop-down revealing a manageable, relevant set of links only when a visitor engages with that section is progressive disclosure doing exactly what it's meant to do.
2: Creates unnecessary friction. Four sequential levels with no overview at any point is a heavy interaction cost, and it compounds with each additional level: this is a case where hiding information has gone too far relative to what it actually saves in screen space.
3: Creates unnecessary friction. Progressive disclosure exists to hide information most people don't need by default. Fees and entry requirements are close to universally needed by anyone reading a course page, so hiding them defeats the purpose rather than serving it.
4: Appropriate. When most visitors genuinely only care about one or two departments out of many, collapsing the rest by default is a reasonable, low-cost way to reduce visual clutter without hiding anything most visitors actually need.
These four examples share the same underlying pattern the concept section describes: progressive disclosure isn't uniformly good or bad, its appropriateness depends entirely on whether what's being hidden is something most visitors need by default. Implementations 1 and 4 hide things most visitors don't need yet. Implementations 2 and 3 hide things most visitors do need, which is where the friction comes from.A reasonable fix for implementation 3: show fees and entry requirements directly on the page by default, with no disclosure control at all, and reserve an accordion instead for genuinely secondary information most visitors wouldn't need immediately, something like detailed accreditation history or a full list of past faculty publications, content that's legitimately useful to some visitors but not central to most people's decision to view the page.