Read the big ideas and the method table, then read the passage and try the six questions without notes.
These are original Marlbridge practice questions, not past exam questions. The passage is fictional and was written by Marlbridge. The rubrics are a suggested Marlbridge rubric, not official scoring. Answers should be balanced and non-political. No calculator is needed.
Big ideas of the unit
- Effects are mixed. Innovations have intended and unintended effects; one effect can be beneficial for some and harmful for others; scale and rapid sharing magnify them (5.1).
- Access, data and voice are connected. The digital divide limits who benefits (5.2); biased data and rules treat groups unequally (5.3); crowdsourced data reflect who takes part (5.4).
- People own and are owned by data. Intellectual property, citation, licences, and wider legal and ethical concerns call for balanced analysis (5.5).
- Safety is designed. PII and aggregated data carry risk; authentication, encryption and updates protect; phishing and other attacks exploit people and software (5.6).
Key relationships and methods
| If the question asks you to… | Use… | Watch out for… |
|---|---|---|
| Describe effects | Name the group, the effect, beneficial or harmful | “People” in general; only one side |
| Evaluate access | Device, connection, cost, skills; equity, access, influence | Only “no computer” |
| Check for bias | Group-by-group results; proxies; representative data | Relying on the overall figure |
| Judge crowdsourced data | Quality and coverage; compare share of data with share of population | Treating size as reliability |
| Use others’ work | Permission and credit; Creative Commons, open source, open access | Mixing up permission and credit |
| Name a threat | Phishing, keylogging, rogue access point, malware | Naming a protection that does not fit |
| Protect data | Strong passwords, MFA, encryption, updates, permissions | Saying “be careful” only |
The passage
CityVoice is a fictional app written by Marlbridge for this review. Residents use it to report problems such as potholes and broken streetlights, vote on which problems the city should fix first, and give small donations to community projects. The app records each report’s location and the reporter’s phone number. The city uses the reports to decide where to send repair crews, and the app’s “priority streets” feature suggests streets to fix using the pattern of past reports. In its first year 60,000 residents signed up. Of 1,800 reports in one month, 900 came from Hilltop (20% of the city’s residents), 600 from Riverside (30%) and 300 from Eastgate (50%). Older residents and residents without smartphones use the app much less. The company that runs CityVoice stores the reports and phone numbers on its own servers.
Question 1 (multiple choice · mixed)
Which part of the passage is the clearest example of crowdsourcing?
- (A) The company stores the reports on its own servers.
- (B) Thousands of residents each submit small reports that the city combines to decide where to send repair crews.
- (C) The app records each report’s location.
- (D) The city has three districts.
Answer and explanation
Answer: (B). Obtaining information from a large number of people via the Internet is crowdsourcing.
- (A) describes where data are kept.
- (C) describes a kind of data collected.
- (D) is background and not a method.
Question 2 (multiple choice · mixed)
The “priority streets” feature uses the pattern of past reports to suggest which streets to fix first. Which concern is best supported by the passage?
- (A) The suggestions may favour districts where many residents report, rather than districts where the need is greatest.
- (B) The suggestions must be unbiased because they use real reports.
- (C) The suggestions cannot be used at all.
- (D) The feature will run slowly.
Answer and explanation
Answer: (A). The pattern of reports reflects who uses the app as well as what is broken.
- (B) real data can still be unrepresentative.
- (C) and (D) are not supported.
Question 3 (multiple choice, select two · mixed)
Which two actions would best protect residents’ personal data in CityVoice?
- (A) Requiring multifactor authentication for staff who can see phone numbers
- (B) Encrypting the stored reports and phone numbers
- (C) Publishing all reporters’ phone numbers so reports can be checked
- (D) Keeping the data forever in case they are useful
Answer and explanation
Answer: (A) and (B).
- (C) would expose PII.
- (D) keeping data longer than needed increases the risk.
Question 4 (constructed response · 5.2, 5.3 and 5.4)
Use the passage.
(a) Calculate the share of the 1,800 reports that come from each district. (3 points)
(b) Compare each district’s share of reports with its share of residents, and say which district appears under-represented. (2 points)
(c) Explain how the digital divide could contribute to this pattern. (1 point)
(d) Describe one change CityVoice could make so that the “priority streets” suggestions are fairer. (1 point)
Answer and explanation
Suggested Marlbridge rubric (7 points).
| Point | Award when the response… |
|---|---|
| 1 | gives Hilltop 900 ÷ 1,800 = 50% |
| 2 | gives Riverside 600 ÷ 1,800, about 33.3% |
| 3 | gives Eastgate 300 ÷ 1,800, about 16.7% (and the shares add to 100%) |
| 4 | says Hilltop has 50% of reports for 20% of residents (over-represented) |
| 5 | says Eastgate has about 16.7% of reports for 50% of residents (under-represented) |
| 6 | links to the digital divide: residents without smartphones or with less access use the app less, so their areas appear less in the data |
| 7 | suggests a fair change (adjust suggestions for the number of residents in each district; combine with inspection data; add other ways to report, such as a phone line) |
Sample response. (a) Hilltop 50%, Riverside about 33.3%, Eastgate about 16.7%. (b) Hilltop has 2.5 times its share of residents’ reports (50 ÷ 20), while Eastgate has only a third of its share (16.7 ÷ 50). Eastgate is under-represented. (c) Residents with no smartphone or less access cannot report, so their streets appear less often in the data. (d) Adjust the suggestions by the number of residents in each district and add inspection data, so that fewer reports from a district do not mean lower priority.
Question 5 (constructed response · 5.1 and 5.5)
Use the passage. A resident posts a photograph of a pothole online under a licence that allows reuse with credit. The city wants to display it in its annual report.
(a) Explain what the city must do to use the photograph legally. (2 points)
(b) The city also finds an open-source mapping library to display the report locations. Explain how this is different from using a fully protected program. (1 point)
(c) Give one benefit and one harm of the city using residents’ reports for purposes beyond fixing the reported problem, such as planning new roads. (2 points)
Answer and explanation
Suggested Marlbridge rubric (5 points).
| Point | Award when the response… |
|---|---|
| 1 | says the city must follow the licence conditions |
| 2 | says the city must credit (cite) the resident |
| 3 | says an open-source program is freely available and may be redistributed and modified (following its licence), unlike a protected program that needs permission |
| 4 | gives a benefit (better planning from real data) |
| 5 | gives a harm or risk (residents did not agree to the new use; the data could reveal personal patterns; the pattern of reports is uneven) |
Sample response. (a) The city must follow the licence’s conditions and credit the resident who took the photograph. (b) An open-source library is freely available and can be modified and shared under its licence, so the city does not need to ask for special permission. (c) Benefit: road planning would use real information about problems. Harm: residents who reported potholes did not agree to their data being used for another purpose.
Question 6 (constructed response · 5.6)
Use the passage.
(a) Identify the PII the app collects and explain one risk if it were exposed. (2 points)
(b) Explain how an attacker could use phishing against CityVoice staff, and one defence. (2 points)
(c) Explain why combining the location of reports with phone numbers could be more revealing than either alone. (1 point)
(d) Explain one way residents could limit the data the app collects. (1 point)
Answer and explanation
Suggested Marlbridge rubric (6 points).
| Point | Award when the response… |
|---|---|
| 1 | identifies the phone number (and location of reports) as PII |
| 2 | explains a risk (someone could contact, track or impersonate a resident; data could be misused) |
| 3 | explains phishing (an email that tricks staff into giving their password or other details) |
| 4 | gives a defence (training staff to spot suspicious messages, multifactor authentication, checking the sender by another route) |
| 5 | says combined data (the places a person reports from, tied to a phone number) can reveal where they live or move |
| 6 | gives a way to limit data (review and restrict the app’s permissions, report without precise location, or not give a number if optional) |
Sample response. (a) The phone number and the location of each report. If exposed, someone could contact or track a resident. (b) Staff might get an email that looks like it is from IT and enter their password on a fake page. Multifactor authentication would limit the damage. (c) Linking locations to a phone number could show where a particular person lives or goes. (d) A resident can restrict the app’s location permission.
How did you do?
If you lost marks on the scenario questions, check whether you named a specific group and a specific action, and used the numbers in the passage. For gaps, return to the topic checklists: 5.1, 5.2, 5.3, 5.4, 5.5 and 5.6.