Reesby Academy · Data & Excel

Data Cleaning in Spreadsheets

Fix messy data so analysis can be trusted.

Beginner · 50 min · 7 lessons · Final quiz · Certificate

About this course

Messy data is normal, and cleaning it is one of the most useful skills you can build in any office job. This course walks you through finding duplicates and blanks, standardising formats and splitting or combining fields. You'll finish with a repeatable routine and a record of every change you made.

What you will be able to do

  • You'll be able to spot duplicates, blanks and inconsistent entries in a spreadsheet
  • You'll be able to standardise dates, names, text and numbers so they can be sorted and filtered
  • You'll be able to split and combine columns safely without losing original data
  • You'll be able to document your cleaning steps so others can repeat or check them

Course outline

  1. Why Data Gets Messy
    7 min · Lesson notes, example, action task · 2-question quiz
    Data usually becomes messy because of people, not computers. Different entry habits, copy-and-paste from other systems and manual typing all leave traces you need to recognise.
  2. Finding Duplicates and Blanks
    8 min · Lesson notes, example, action task · 2-question quiz
    Duplicates and blanks can distort totals and cause double contact with customers. Finding them systematically, rather than by scrolling, saves time and avoids mistakes.
  3. Standardising Formats
    8 min · Lesson notes, example, action task · 2-question quiz
    Standardising means choosing one correct format for each type of value and applying it everywhere. This makes sorting, filtering and reporting reliable.
  4. Splitting and Combining Fields
    7 min · Lesson notes, example, action task · 2-question quiz
    Some data is stored in one column when it should be in two, such as a full name or an address. Splitting and combining let you reshape it, but you need to do it without losing the original.
  5. Documenting Your Steps
    8 min · Lesson notes, example, action task · 2-question quiz
    A cleaning process that nobody can repeat is a risk. Documenting what you did, why and how many records were affected lets colleagues trust, check and reuse your work.
  6. Tools you'll need
    6 min · Lesson notes, example, action task · 2-question quiz
    You can clean most office data with tools you probably already have. Start free, then move to paid tools only when your data volume or sharing needs call for it.
  7. Careers & next steps
    6 min · Lesson notes, example, action task · 2-question quiz
    Data cleaning skills are used in analysis, operations, finance and reporting roles. This lesson sets out where they lead and how to check what the work is worth.
  8. Final quiz and certificate
    10 questions, pass mark 8 of 10. Pass to get your Reesby Academy certificate with a verification link.

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