4.2Charts & graphs
The essentials in 30 seconds
- A chart visualizes the report summaries: a category on the axis (often a group: region, month) and a value as height (often a summary: total sales).
- The type follows the message: bars to compare categories, line for a time trend, pie for shares of a whole with few categories.
- Farès's reflex: a chart in the report footer for the global view, one per group for detail by category — clear title, few series, sober colors.
Threaded mini-case — Farès and the sales summary by region
Farès, a controller in Algiers, presents the monthly summary to management: his table of figures by region is never read. He inserts a bar chart via the Chart Expert — category: Region group, value: total sales — placed in the report footer for the global view, with an explicit title and sober colors. For monthly tracking, he adds a line chart of sales by month that reveals seasonality. Second milestone of the thread: the same figures, turned into a message visible at a glance.
Continued from case 4.1 — Farès makes the subreport-enriched statement visual.
1. Visualizing report data: category and value
A report is not limited to tables: charts make data speak at a glance. Via “Insert → Chart / Chart Expert”, you get histograms and bars, lines, pies and doughnuts, and other types. Like Farès's bar chart, the chart relies on the report's groupings and summaries: a category on the axis (often a group: region, month — “On change of”) and a value as height (often a summary: total sales — “Show value”).
With no group or summary, there is no reliable chart: the chart turns the report totals into a visual. It refreshes when the data refreshes.
2. The right type for the message
Choose the type for what you want to show: bars to compare categories (sales by region, revenue by product — the most versatile; horizontal bars if labels are long), line for a time trend (sales by month — reserved for ORDERED data), pie for shares of a whole (breakdown in %, with FEW categories: 3 to 6).
A wrong type blurs the message: a pie with 20 slices is unreadable (switch to bars or group into “Others”); a line connecting unordered categories suggests a false continuity. Choosing the type is the most important decision for an effective chart.
3. Placement and readability
Placement sets the scope: report footer or header = one global chart shown once (Farès's summary); group header or footer = one chart PER group, repeated for each category (powerful but it lengthens the report).
Stay readable: clear title (“Sales by region — current month”), legible legend and labels, few categories and series (Top N in 3-5 or grouping into “Others”), sober and consistent colors, sufficient size, formatted axes. Do not overload the report with charts: one clean visual adds impact, a confusing visual harms clarity.
Did you know?
Comparing means aligning bars — not cutting a pie into confetti.
🔎 Concrete example — 🔎 Concrete example — Sales by region
Farès's summary: a readable bar chart, placed in the right spot.
Type: bars (compare categories).
Category (on change of): Region group.
Value (show value): Sum(Ventes).
Placement: Report Footer (global view).Reading: compare → bars; category = group, value = summary; global scope = report footer.
Lesson: a comparison visible at a glance, which refreshes with the data.
Section vocabulary
- Chart
- VISUAL representation of report data (usually summaries by group): bars, lines, pies. Makes trends and comparisons immediate.
Simple example: Farès replaces the table of figures with a bar chart of sales by region.
What it is not: a decorative picture unrelated to the data.
Reflex: figures never read: turn the totals into a visual.
- Chart Expert
- Setup assistant: type, data (category and value), placement, title, legend and colors.
Simple example: Farès sets bars, the Region group and total sales there in a few clicks.
What it is not: a freehand drawing to build by hand.
Reflex: new chart: go through the Chart Expert, not DIY tinkering.
- Category and value
- What goes on the axis (CATEGORY — often a group) and as height (VALUE — often a summary).
Simple example: Region as category, total sales as value in Farès's summary.
What it is not: two raw fields with no grouping or total.
Reflex: before any chart: check group + summary.
- Chart placement
- Report footer or header = single GLOBAL chart; GROUP header or footer = one chart PER group. Sets the scope.
Simple example: Farès puts the global summary in the report footer, not in a group.
What it is not: a mere aesthetic choice with no consequence.
Reflex: an overview or a per-category view: place accordingly.
In practice — In practice — Insert a chart
- Insert a chart (“Insert → Chart / Chart Expert”) on a grouped and totaled report.
- Choose the TYPE for the message (bars to compare, line for a trend, pie for shares); set the CATEGORY (a group) and the VALUE (a summary).
- Place the chart for the scope: Report FOOTER (global) or GROUP footer (one per group).
- Polish title, legend and colors; check readability (not too many categories or series) and the preview rendering.
Ready-to-say script — present the summary to management (30 s)
“This is Farès: here are sales by region in one chart — bars compare, the line shows the monthly trend. The detailed figures stay in the table, but the decision is made here, at a glance.”
Say in committee: leave the table as an appendix and project the chart.
Copy-paste template — chart scoping sheet
Message: [compare regions | track monthly trend | show shares]
Type: [bars | line | pie (≤ 6 slices)]
Category: [Region group | Month group] — Value: [Sum(Ventes)]
Placement: [report footer — global | group footer — one per group]
Finish: title [Sales by region — current month], legend [yes], colors [sober]Management summary
Like Farès: one global bar chart in the report footer, explicit title — the decision in one look.
Monthly tracking
Line chart of sales by month: seasonality and trends appear immediately.
Share breakdown
Pie with 4-5 categories maximum, small values grouped into “Others” to stay clean.
Analysis by category
One chart per group (e.g. per region) to compare each category visually — watch the length.
✓ Best practices
- Bars to compare, line for time, pie for shares (few categories).
- Order bars by value (ranking) for clarity.
- Group small values into “Others” for a clean pie.
✗ Common pitfalls
- Overloaded pie (too many slices, unreadable).
- Line on unordered categories (false continuity).
- Too many overlapping series (confusing chart).
Key takeaways
- CHARTS visualize report data (usually SUMMARIES by group): bars, lines, pies. Inserted via the Chart Expert.
- Set the CATEGORY (axis — often a group) and the VALUE (height — often a summary).
- Choose the right TYPE for the message: BARS (compare), LINE (trend), PIE (shares, few categories).
- PLACEMENT sets the scope: report footer = global; GROUP footer = one per group. Stay READABLE.
48h challenge — apply tomorrow
On a real figures report: add 1 chart (type for the message, category + value), place it for the wanted scope and have it reviewed by a colleague in 10 seconds.
- I can insert a chart with a category (group) and a value (summary).
- I can choose the type for the message (compare, trend, share).
- I can place the chart for the scope and keep it readable.
Frequently asked questions
Which chart type should I choose for the data to show?
The type must match the MESSAGE. BARS: compare categories (sales by region) — the most versatile, horizontal if labels are long. LINE: trend over TIME (sales by month) — reserved for ordered data. PIE: shares of a WHOLE in % — only with FEW categories (3 to 6, otherwise unreadable). Common mistakes: overloaded pie (switch to bars or group into “Others”), line on unordered categories (switch to bars), too many series. Choose by “compare, trend, share” and stay sober.
Where should I place a chart and how do I keep it readable?
Scope by section: report footer or header = single GLOBAL chart (summary, the most common); GROUP header or footer = one chart PER group (repeated per category — powerful but lengthens the report). Readability: limit categories and series (Top N, “Others”), clear title, legible legend and labels, sober and consistent colors, sufficient size, formatted axes, consistency with totals. A well-placed, clean chart adds impact; an overloaded or misplaced one harms clarity.
Which type compares sales across regions?