A spreadsheet only helps you solve a real problem if the data is tidy. Messy headings, blank rows, mixed number formats, and merged cells in the middle of a table quietly break sorting, filtering, and formulas later. Today you will learn the input rules professionals use, practise them on a deliberately messy stock list, then clean the project spreadsheet you started from a template.
You need the workbook from the template lesson: {{code:sm3_from_template}} in {{code:Project_Portfolio/09_specialism/sm3}}. If you have not got it, tell your teacher — they will give you a short starter list to save under that name.
Think about a list you keep somewhere (Work Experience hours, side-hustle stock, club kit, or creator analytics). If one column mixed plain numbers with values like "about €12", and a blank row sat in the middle, what would go wrong the first time you tried to total or sort it?
These five rules keep a data table usable for formulas, charts, filters, and printouts later in Module 3. Your teacher will point at each problem on the messy demo sheet first; use the table as your checklist.
| Concept | Why it matters | Example |
|---|---|---|
| Headings in row 1 — the first row names each column; data starts on row 2 | Sort, filter, charts, and many templates expect labels on row 1 | Row 1: Item, Unit cost (€), Qty sold — not a merged banner saying "MY STOCK" |
| One fact per row — each row is one item, day, person, or record | Totals and averages only make sense when every row means the same kind of thing | One Work Experience day per row (date, start, end, hours) |
| Consistent column types — numbers stay numbers, dates stay dates, text stays text | A cost column cannot total if some cells are text like "€12.50" or "about 10" | Store 12.5 and apply currency format (€), rather than typing the euro symbol by hand |
| No blank mid-table rows — empty rows do not sit inside the block of data | Blank rows split a table so sort, filter, and autofill stop halfway | Five stock lines in rows 2–6 with no empty row between items |
| No merged cells in the data area — merge only decorative titles outside the table, if at all | Merged cells break sorting, filtering, and many formulas that need a clean grid | Separate columns for Name and Role, not one merged "Aoife — Supervisor" cell |
Target shape: row 1 holds plain headings, continuous item rows underneath, costs are real numbers with currency formatting, and nothing in the data block is merged. That is the standard you will apply to your own project sheet.
Work lockstep with your teacher on a deliberately messy stock list for a phone-case side hustle, then clean it against the five best-practice rules. If your teacher shared a pre-messed {{code:sm3_data_input_practice}} file, open that and join from the pause-and-scan step. Otherwise build the mess first, then clean it together on screen.
| Issue | Solution |
|---|---|
| After I unmerge a title, the text only sits in one cell and looks wrong | That is normal. Keep the wording only if you still need a title above the table; otherwise delete it and put real column headings on row 1 |
| My costs still will not add up after cleanup | Click a cost cell and look at the formula bar. If you still see a euro sign or words like "about", retype a plain number and apply currency formatting |
| I deleted a blank row and my headings jumped to the wrong place | Use Undo ({{kbd:Ctrl+Z}} or {{kbd:Cmd+Z}}), check the row numbers in the steps, then move headings to row 1 with cut and paste before you delete anything else |
| The sheet still has a gap between headings and the first item | Delete each empty row under the headings so row 2 is the first real record |
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