Cell Tooltip Reference
Overview
It is easy to assume a table needs no tooltip — everything worth knowing is already a column, right? In practice, every cell in the visual carries more figures than are ever displayed: a raw (unweighted) base, a weighted base, the base of whatever it was statistically compared against, an index, both percentages, and — with significance testing on — a continuous confidence level behind the pass/fail marker. The Cell Tooltip surfaces this "hidden" layer on hover, using Power BI's native tooltip (so it matches the report's theme and positions itself correctly), without cluttering the table itself.
Scope
Cell Tooltip is available on both CrossTable and CrossTable InCell Charts — same settings, same content, same behavior. This also covers merged cells: when Data Bar or Data Line "Group into one chart" fuses several series into a single cell (one <td> holding multiple bars/points), hovering it shows one set of tooltip lines per series, labeled by that series' column path — same content options as an ordinary cell, just repeated once per merged series.
Activation
Card: Tooltip Setting: Activate Tooltip Type: Toggle Default: Off
The tooltip is opt-in. Once activated, a Tooltip content sub-card appears with one toggle per piece of information you want to expose.
Tooltip content
| Setting | Shows | Default |
|---|---|---|
| Row levels | The full row header path (every level, from the outermost to the innermost) for the hovered cell | On |
| Column levels | The full column header path (every level) for the hovered cell | On |
| Value | The cell's value — a count in a percentage table, the average in a mean table | On |
| Vertical % | The cell's vertical percentage (percentage tables only) | On |
| Horizontal % | The cell's horizontal percentage (percentage tables only) | Off |
| Index | The cell's index | Off |
| Weighted base | The cell's weighted base (the same figure used as the significance test's own denominator) | Off |
| Unweighted base | The cell's unweighted (respondent) base | Off |
| Compared base | The base of the group this cell was statistically compared against (see below) | Off |
| Significance confidence level | The continuous confidence level of the active significance test(s) (see below) | Off |
Vertical % and Horizontal % are automatically skipped on mean tables even if toggled on — percentages have no meaning there. Everything else (Value, Index, both bases) applies to both table types.
Row and column levels are labeled Row / Column when the table has a single level, or Row 1, Row 2… / Column 1, Column 2… when it has several — matching the order they appear in the header hierarchy, outermost first.
Value, Weighted base and Unweighted base reuse the labels you already configured elsewhere, so the tooltip stays consistent with the rest of the table:
- Value uses the measure's display name (the same label used on single-indicator column headers).
- Weighted base / Unweighted base reuse the Base row label / Unweighted row label settings from Totals & Subtotals, even if those base rows are not currently displayed in the table.
Numbers in the tooltip are rounded to the same number of decimals the table itself uses for that figure — the Table options card's precision for Value/Base/Unweighted base on mean tables (0 on percentage tables), and the configured precision for Vertical %/Horizontal %. The tooltip never applies its own, unrelated rounding.
Significance confidence level
Every significance test already produces a pass/fail marker (icon, font color, background or border — see Significance Testing) based on the Significance level threshold you configured (90%, 95% or 99%). That threshold necessarily throws information away: a cell that misses a 95% threshold by a hair looks identical to one that is nowhere close.
The tooltip instead shows the actual, continuous confidence level the underlying statistical test reached for that cell — for example +92.5% or −98.8% — computed from the same z/t statistic the pass/fail test already uses, just not discarded after the comparison.
- The sign follows the same convention as the pass/fail marker: + means the cell is higher than what it was compared against, − means lower.
- The magnitude is independent of the Significance level setting — it does not change if you switch that setting from 90% to 99%. Only the pass/fail marker's threshold changes; the confidence level itself is a property of the data.
- If more than one significance test is active on a cell (Significance 1/2/3), the tooltip lists one Confidence level line per active test, in the same order as the tests.
A cell marked "not significant" at your chosen 95% threshold but showing a tooltip confidence level of 91% is a near miss, worth a second look. A cell showing 12% is nowhere close. The pass/fail marker alone cannot tell you which is which — the tooltip can.
Compared base
Every significance test compares the cell against something: the complement of the same row, the table's grand total, a regex-matched reference column, the previous visible column, or the previous row. Compared base shows the base of that other side of the comparison — the denominator the cell was actually tested against, not the cell's own base.
| Active test type | What "Compared base" shows |
|---|---|
| Item vs Other Question Item (complement) | The base of everything else in the row (the complement) |
| Item versus Total (Base) | The table's grand total base |
| Regular expression | The base of the regex-matched reference column |
| Previous visible column / Previous row | The base of the previous visible column or row it was compared against |
| All Columns | (not available — this mode compares against every other column at once, so there is no single "compared" base) |
If more than one significance test is active on a cell, the tooltip lists one Compared base line per active test — numbered Compared base 1, Compared base 2… in the same order as the tests, exactly like Significance confidence level above.
Gap Mode cells
On CrossTable InCell Charts, a cell that belongs to a Gap Mode column doesn't hold an ordinary value — it holds the gap itself (main partition − reference). On a percentage table, the number that actually drives the bar/label is the gap of the vertical percentage, not a gap of raw counts — so the plain Value line would show an unrelated figure. The tooltip handles this by substituting the driving line (Vertical % on a percentage table, Value on a mean table) with three lines instead of one:
| Line | Shows |
|---|---|
| (metric) (Gap) | The gap actually shown on the bar/number — main partition minus its reference. |
| (metric) (Raw) | The main partition's own value, before the gap was computed. |
| (metric) (Reference) | The value it was compared against (the group's average for "Gap vs average", or the named competitor for "Gap vs 2nd/3rd"). |
(metric) is Vertical % or the measure's display name, matching whichever one is actually driving that gap column. All three are rounded to that gap column's own Precision setting (the ⚙ editor), not the table's general precision — since that is the precision the column is actually rendered at.
This trio only replaces the driving line; the table's ordinary Compared base and Significance confidence level (borrowed from the significance test assigned to that gap column, see Significance drives color) still work normally on gap cells.
How it renders
The tooltip is wired to Power BI's native tooltip service (host.tooltipService), the same mechanism used by built-in visuals, so it:
- follows the report's light/dark theme automatically,
- positions itself relative to the pointer and stays within the report canvas,
- does not require any extra configuration for touch devices.
Internally, a single set of event listeners is attached to the table (not one per cell), so activating the tooltip has no measurable performance impact even on large tables.
Troubleshooting
Q: I toggled a content option but nothing changed in the tooltip A: Check that Activate Tooltip is on — the content sub-card only takes effect once the feature itself is enabled.
Q: Vertical %/Horizontal % don't appear even though I enabled them A: You are looking at a mean table — percentages are not meaningful there and are always skipped (see Tooltip content above).
Q: Compared base is empty A: The cell's active significance test is All Columns, which has no single comparison partner (see Compared base), or no significance test is active on that cell at all.
Q: Significance confidence level is empty A: No significance test is active for that cell, or Significance testing itself is not configured.
Q: On a Gap Mode column, Value/Vertical % shows a number I can't reconcile with the bar A: That's the Gap Mode cells case — the driving line is replaced by a Gap/Raw/Reference trio automatically; look for those three lines instead of the plain one.