Why this matters
Three spreadsheet skills come up again and again in Ghanaian data and M&E adverts and in interview tests: looking up values from another table, stopping bad entries with validation, and summarising with pivot tables. Master these and you can handle most reporting tasks a junior role will give you.
Lookups: joining two tables
Often the information you need sits in two places. Imagine an invented sheet of sales that lists only product codes, and a second sheet called Prices that lists each code with its name and price. A lookup brings the price across into the sales sheet.
In Google Sheets and newer Excel, use XLOOKUP:
=XLOOKUP(B2, Prices!A:A, Prices!C:C)
This says: find the code in B2 inside column A of Prices, and return the matching value from column C. If the code is missing, XLOOKUP shows an error, which is useful: it tells you something is wrong.
Many workplaces still use the older VLOOKUP:
=VLOOKUP(B2, Prices!A:C, 3, FALSE)
Here 3 means "the third column of the range", and FALSE means "exact match only". Forgetting FALSE is a classic mistake that returns wrong prices without any warning, so always include it.
Validation: stopping bad entries
Data validation limits what can be typed in a cell. A dropdown list of community names means nobody can type "Tamal" or "tamale metro" by accident. You can also limit numbers, for example ages between 0 and 120. In Google Sheets, open Data, then Data validation, and choose a rule. Validation is cheaper than cleaning: every mistake it stops is one you never have to fix.