Mixing the two makes people misread scope
Aliases: scope misread · mixed global local · nav region confusion
What it is
Global items are site-wide; local items are current-branch. Put them in the same visual strip, in the same style, with no grouping, and people cannot read scope from position. Mixing them causes scope misread: a branch-only entry is taken as available everywhere, or a site-wide entry is taken as “only on this page.” The expectation is already wrong before the click; the blame after the click lands on the whole nav.
What is misread is not a wrong label. It is scope that the visual structure failed to say.
Why it happens
Scope is inferred from grouping and position by default. The middle of a top bar is read as site-wide; a sidebar or secondary bar is read as “this region.” Mixing breaks that convention. Insert “Returns policy” into the top bar and people will believe every section has its own returns policy reachable from the top bar; demote “Products” into the current section’s sidebar and people will believe they cannot reach Products once they leave this page. One misread rewrites the starting point of later jumps—looking in local when they should change branches, running to global when they should stay in-branch.
Shared styling also encodes scope. If local items match global items in size, color, and hit area, even nearby grouping will not be read. Marketing often lifts a campaign’s local entry into the global strip for exposure. Clicks rise in the short run; in the long run that item’s scope is taught wrong: after the campaign ends, people still hunt it in the global strip, or they assume other local entries can be lifted too.
Studying it
Ask about scope; do not only ask “what would you click.”
- Paradigms: mixed versus grouped nav screenshots, item by item: “does this entry still exist in another section?”; then a cross-page task: from branch A, click a local item that was inserted into the global strip, and see whether people expect it in branch B’s top bar.
- Independent variables: whether global and local occupy separate regions, whether they share a style, whether a local item is promoted into the global strip.
- Dependent variables: accuracy of scope judgments, hunts for a promoted item after changing branches, treating a global item as an in-branch entry.
- Methodological note: staff know which items are site-wide and will mask mixing damage. Recruit people who have not seen the site. The probe must name “is it still there on other pages,” or people will pick by scent and the study will not measure scope.
Where it stops holding
Tiny tools with two or three global items and two or three local ones may still separate them by copy (“Account” versus “This chapter”), but vague copy collapses into misread immediately. Responsive wrapping that dumps both bars into one hamburger makes mixing almost inevitable; the hamburger still has to group inside. Personalized slots inserted into the global strip are the system mixing on the user’s behalf; the misread then drifts as recommendations change.
Applying it
- Keep global and local apart: different bars, different columns, or two labeled groups inside one container. Do not make one undivided strip of words.
- When a local item needs exposure, strengthen it in the local region; do not promote it into the global membership list.
- Inside a hamburger, keep “site-wide / this section” as two blocks; after close, do not leave a local item sitting in a global slot in the visible chrome.
- Verify by handing a nav screenshot to someone uninvolved and asking, item by item, “if you change section, is this still there?” Every wrong answer is a scope misread from mixing. Then pick a local entry that was judged “site-wide,” change section, and see if it remains—if it does, it has been wrongly globalized and should be pulled back.