A mechanism is the chain of steps that explains why better access to a service changes people’s outcomes. Examiners reward chains of three or four linked steps in longer answers. This lesson follows comparing indicators and prepares you for reading inequality data in development and inequality.
All villages and figures here are invented.
How do you build a chain step by step?
- Name the access. What is now available, and to whom? For example, a tap within the village.
- State the first effect. What changes in daily life? Time, cost or safety.
- Link to a second effect. What does that change allow or prevent?
- Reach the outcome. Name the indicator affected, such as school attendance or illness rates.
- Check each arrow. Ask “why does this follow?” If you cannot answer, add a step.
Worked example
Before a tap is installed, people in an invented village walk to a distant stream for water. A round trip takes 2 hours a day. After installation it takes 20 minutes.
Time saved: 2 hours = 120 minutes. 120 − 20 = 100 minutes a day, which is 1 hour 40 minutes.
Over a school week of 5 days: 100 × 5 = 500 minutes, which is 500 ÷ 60 = 8 hours 20 minutes.
Chain: A tap in the village means the water walk takes 20 minutes instead of 2 hours. This frees about 8 hours 20 minutes a week, which can be spent in school or earning. Safe tap water also lowers exposure to waterborne illness, so fewer days are missed through sickness. As a result, school attendance can rise and household income can become more stable.
Notice how each sentence builds on the one before. The verb “can” is honest, because the example shows a possible effect and not a certain one.
What mistake should you watch for?
Mistaken answer: “Access to clean water improves health and education.”
This states two outcomes but no steps. It would earn little, because the examiner cannot see how the writer thinks water leads to either outcome.
The correction is to add the middle links: access, less time collecting water and fewer waterborne illnesses, so more days in school, so better attendance. Every arrow needs a reason that a reader could challenge.
Check yourself
All data are invented.
1. A family used to spend 90 minutes a day collecting water. After a new pipe, it takes 15 minutes. How much time is saved per week of 6 days?
Show answer
90 − 15 = 75 minutes a day. 75 × 6 = 450 minutes. 450 ÷ 60 = 7.5 hours (7 hours 30 minutes) a week.
2. Put these in a logical chain: more days in school; a clinic opens in the district; shorter travel time to treatment; illnesses treated earlier.
Show answer
A clinic opens in the district, so travel time to treatment is shorter, which means illnesses are treated earlier, so fewer days are missed and there are more days in school.
3. Add one missing step: “Electricity reaches the village, so exam results improve.”
Show answer
“Electricity reaches the village, so homes have lighting in the evening, which means students can study after dark, so exam results can improve.”
Where does this lead next?
Next, read how inequality is shown in data in interpreting a supplied inequality graph. The statistics and distribution explorer supports the number work behind these chains. If you want a teacher to check your chains against the wording of a real question, see online one-to-one Geography tuition.