The school office and 240 absence notes
A school office gets 240 absence notes in one term. Today somebody types each one into a plain box.
Two ideas: a smart screen with drop-downs that is slow to build but quick to use, or the plain screen that is built already. Which is better?
The answer depends on three things. You will find out which.
Key words
| Word | What it means | Example |
|---|---|---|
| Data entry screen | The page or form where a person types or picks data. | A sign-up form |
| Build time | The hours it takes to make the screen. | 6 hours |
| Expertise | The skill and knowledge needed to do a job well. | Knowing how to build a form |
| Entry time | The time it takes a person to put the data in. | 3 minutes for each form |
| Data quality | How correct, complete and useful the data is. | Few mistakes in the list |
| Trade-off | You give up one good thing to get another. | More build time for fewer errors |
| Judgement | A choice you can explain with reasons. | Build it, because there are many forms. |
| Validation | A check that a value is sensible. | Age from 11 to 19 |
The cells students fill in are left blank in this preview.
Quick check: three factors
Have a go
Quick check: three factors
3 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.
Three factors
Three things change how you set up data entry.
Time to build the screens. A better screen takes longer to make.
Expertise to build them. You need people with the right skills. They cost money or time.
Time to enter the data. A slow screen costs time on every form, again and again.
Worked example: which screen takes less time?
| Step | Plain boxes | Drop-downs |
|---|---|---|
| Build time | 2 hours | 6 hours |
| Time for one form | 3 minutes | 1 minute |
| 120 forms: minutes | 120 x 3 = 360 | 120 x 1 = 120 |
| 120 forms: hours (60 minutes in an hour) | 360 / 60 = 6 | 120 / 60 = 2 |
| 120 forms: total hours | 2 + 6 = 8 | 6 + 2 = 8 |
| 240 forms: total hours | 2 + 12 = 14 | 6 + 4 = 10 |
The cells students fill in are left blank in this preview.
Try it: count the hours
forms = 240
plain = 2 + forms * 3 / 60
dropdown = 6 + forms * 1 / 60
print("Plain boxes:", plain, "hours")
print("Drop-downs:", dropdown, "hours")
# Change forms to 60 and press Run again. Which screen is better now?
Quality is a factor too
The table counts only time. There is one more thing: mistakes.
A drop-down menu stops spelling mistakes. Validation stops silly values. Fewer mistakes means better data quality. Bad data costs time later, when somebody must find and fix it.
Methods compared
| Method | Build time | Expertise | Entry time | Quality |
|---|---|---|---|---|
| Plain boxes, no checks | Low | Low | Medium | Low |
| Plain boxes with validation | Medium | Medium | Medium | Medium |
| Drop-down menus | Medium | Medium | Low | High |
| Double entry for key fields | Medium | Medium | High | High |
| Pre-filled boxes | Medium | Medium | Low | Medium |
The cells students fill in are left blank in this preview.