Nobody has time to clean it
A council has a survey file of 3,000 resident replies. Half the postcodes are in the wrong format.
Everyone agrees it should be fixed. But it takes 30 hours, a person who knows the data and a budget. So it does not happen. Keeping data good always has a price.
Key words
| Word | What it means | Example |
|---|---|---|
| Maintain | To keep data accurate and up to date. | Fix wrong postcodes |
| Time | The hours it takes to do the work. | 30 hours |
| Skills | What the people doing it need to know. | Knowing the survey system |
| Cost | The money the work uses. | 20 pounds an hour |
| Trade-off | Giving up one good thing to get another. | Less checking for lower cost |
| Validation | A check that data is sensible and in the right shape. | A code must have four digits. |
| Verification | A check that data was copied correctly. | Type it twice. |
| Metadata | Data that describes other data. | Owner and date |
| Automate | To make a computer do a repeating job. | A nightly check |
The cells students fill in are left blank in this preview.
By the end of this lesson
Note
I can explain how time, skills and cost affect keeping data good.
Starter: what you already know
Have a go
Starter: what you already know
3 questionsHave a go: your answers are marked here and then forgotten. Sign in if you would like your score kept, and to pick up where you left off.Sign in to keep your score
Your answers are marked here and are not kept. A college account keeps every student’s marks.
Three factors affect upkeep
Three things decide how well data is maintained.
- Time. Checking, cleaning and updating take hours that could be spent elsewhere.
- Skills. People need to know the system, the data and the rules. A wrong fix can do harm.
- Cost. Time and skills cost money. Training, software and staff all add up.
Worked example: cleaning a survey file
| Step | Number | Meaning |
|---|---|---|
| Records to check | 250 | The size of the job |
| Records checked in an hour | 100 | How fast one person works |
| Hours needed | 3 | 250 is two full hours and half of another, so round up to 3 |
| Hourly rate | 20 pounds | The cost of the person |
| Total cost | 60 pounds | 3 hours times 20 pounds |
The cells students fill in are left blank in this preview.
Check: time, skills or cost?
Have a go
Check: time, skills or cost?
3 questionsHave a go: your answers are marked here and then forgotten. Sign in if you would like your score kept, and to pick up where you left off.Sign in to keep your score
Your answers are marked here and are not kept. A college account keeps every student’s marks.