Judging whether collected data is essential

Name:

Date:

Class:

Quick Questions

Shade in the A or B circle for each question.

1. A school library app lets students borrow books. Is a student's library card number essential data?

A Yes - the app can't record who borrowed a book without it

B No - the app could still work without it

2. A pizza shop app delivers pizzas to homes. Is the customer's favourite football team essential data?

A Yes - the app can't deliver without it

B No - pizzas can still be delivered without it

3. Which question is the best test for judging if data is essential?

A Could the system still work without this data?

B Would this data be interesting to have?

4. An online game needs a username so players can log in and appear on the leaderboard. Is the username essential?

A No - the game works the same without it

B Yes - the game can't work for each player without it

5. A homework reminder app sends alerts to a student's phone. Which is the better reason for collecting their home address?

A There is no good reason - reminders work without an address, so it is optional

B It is essential - every app needs an address to work

Match the Pairs

Draw a line connecting each item on the left to its match on the right.

Left column		Right column
1Pizza app form: delivery_address (required)		AShoe size is not needed to borrow books. The app works without it, so it is optional and should not be collected.
2Pizza app form: favourite_colour (optional)		Bemail: essential because the login code is sent to it
3The test: ask whether the system could still do its purpose if the data was left out. If it could, the data is optional.		CIF works_without(data) THEN optional
4Giving a reason: explain what the system could not do without the data.		D'Might be useful later' is not a good reason. Data is essential only if the system cannot do its purpose without it right now.
5Library book app: shoe_size = essential		EOptional data: the app still works without it, so it does not need to be collected
6phone_number: essential because we might want it later		FEssential data: the app cannot deliver the pizza without it

Definitions

essential data

Fill in the Blanks

Complete each line of code by filling in the missing parts.

IF system still works without the data THEN data is ________ ELSE data is essential

Test: could it still work without this? If __, the data is essential.

app <- "pizza delivery" data <- "home address" essential <- ____

app <- "online maths quiz" data <- "home address" essential <- _____

Data: username for a game account Reason: account cannot work without it Verdict: _________

Spot the Error

Shade in the letter of the line that contains an error.

Question 1

A purpose ← "deliver a parcel"

B data ← "delivery address"

C IF no data, can still deliver

D THEN essential ← TRUE

Question 2

A purpose ← "play a quiz game"

B data ← "shoe size"

C IF no data, cannot play

D THEN essential ← TRUE

Question 3

A purpose ← "play music"

B data ← "email address"

C IF no data, cannot send

D THEN essential ← TRUE

Question 4

A essential data: nice to have

B optional data: can be left out

C shoe size for pizza: optional

Question 5

A data ← "pet name"

B IF app breaks without data

C THEN data is optional

D Leave it out of the form

Answer Key

Judging whether collected data is essential

Section A: Quick Questions

A — Yes - the app can't record who borrowed a book without it

B — No - pizzas can still be delivered without it

A — Could the system still work without this data?

B — Yes - the game can't work for each player without it

A — There is no good reason - reminders work without an address, so it is optional

Section B: Match the Pairs

Pizza app form: delivery_address (required) → Essential data: the app cannot deliver the pizza without it

Pizza app form: favourite_colour (optional) → Optional data: the app still works without it, so it does not need to be collected

The test: ask whether the system could still do its purpose if the data was left out. If it could, the data is optional. → IF works_without(data) THEN optional

Giving a reason: explain what the system could not do without the data. → email: essential because the login code is sent to it

Library book app: shoe_size = essential → Shoe size is not needed to borrow books. The app works without it, so it is optional and should not be collected.

phone_number: essential because we might want it later → 'Might be useful later' is not a good reason. Data is essential only if the system cannot do its purpose without it right now.

Section C: Definitions

essential data — Data a system cannot do its purpose without. If the system could still work with it left out, the data is optional and does not need to be collected.

Section D: Fill in the Blanks

IF system still works without the data
THEN data is optional
ELSE data is essential

Test: could it still work without this?
If no, the data is essential.

app <- "pizza delivery"
data <- "home address"
essential <- true

app <- "online maths quiz"
data <- "home address"
essential <- false

Data: username for a game account
Reason: account cannot work without it
Verdict: essential

Section E: Spot the Error

C — The test for essential data is 'could it still work without this?'. A parcel cannot be delivered without an address, so the line should say 'IF no data, cannot deliver'. As written, the test says the data is not needed, which contradicts the conclusion on line 4.

B — A quiz game still works without your shoe size, so it is optional data. Line 3 says the game cannot be played without the data, so line 2 should name data the game really needs, such as "username".

A — The purpose does not match the rest of the program. An email address is essential for sending an email, so line 1 should be purpose ← "send an email". Playing music does not need an email address.

A — Essential data is data the system cannot do its purpose without. 'Nice to have' describes optional data. The line should read 'essential data: needed to work'.

B — The test should check whether the app still works without the data. If it does, the data is optional. Saying the app breaks would make the data essential, which contradicts lines 3 and 4. It should be 'IF app works without data'.