Factors and circumstances
The four kinds of factor the standard names
- The Explanatory Notes list four: elements, processes, events and perceptions. All four are named, so a submission built only on processes has used a quarter of the list.
- Elements are the things that are there: the harbour, the ring road, the flat land, the rail line, the university, the industrial zoning. Elements are states, not actions.
- Processes are sequences of action that change things over time: suburbanisation, gentrification, decentralisation, intensification, migration. A process has a direction and takes years.
- Events are single, dated occurrences: a motorway opening in 2004, a factory closing, an earthquake, a zoning change passed by council. Events are the easiest factor to evidence because they have a date.
- Perceptions are what people believe about a place, true or not: that a suburb is unsafe, that a street is trendy, that the CBD has no parking. Perceptions change behaviour, and behaviour changes the pattern.
- A second label sits across those four. A factor is natural (relief, a river, the coastline) or cultural (decisions, money, law, belief). Urban patterns are usually dominated by cultural factors, but the natural ones set the board — Tawharau's harbour blocks growth north, so the city could only grow in three directions.
Why perceptions carry more weight than students expect
- Perceptions are named in the standard and are the factor most often left out.
- A perception does not have to be accurate to be a cause. If people believe the CBD has no parking, they shop at the mall, whatever the parking count says.
- Perceptions are measurable with a short survey or rating scale, so they produce evidence you can quote.
- Perceptions explain the direction of a change that other factors only permit. Cheap inner-city housing makes gentrification possible; a change in what people think about inner-city living makes it happen.
- Perceptions differ between groups, and the difference is usually the most interesting thing in the submission. In the invented Tawharau, 72 per cent of over-60s surveyed described the CBD as unsafe after dark against 31 per cent of under-30s, and the two groups shop in different places as a result.
Explaining the variation, not the pattern
- This is the shift at Merit, and it is worth reading twice. Achieved asks you to explain the factors behind the pattern. Merit asks you to explain the factors behind the variation.
- A factor that explains the whole pattern equally explains none of the variation. Land is expensive in cities is true of every part of Tawharau, so it cannot explain why one part differs from another.
- Tie each factor to the part of the variation it accounts for. Land value explains the difference in store size; road access explains where the second peak is; distance from the CBD explains which strips have empty shops.
- The test: does this factor vary? Only a factor that varies across the city can explain variation across the city.
- Say which part of the variation each factor does not explain. Naming a factor's limit is a cheap way to look convincing, and it is honest.
Building an explanation chain that holds together
- State the factor, then the mechanism, then the effect on the pattern. Three steps, in that order, every time.
- The mechanism is the step students drop. The ring road caused the big-box strip names a factor and an effect with nothing between them. The mechanism is that a big-box store's catchment is measured in driving minutes, so the more vehicles pass, the larger the catchment — and 20,000 vehicles a day pass that junction.
- Attach a figure to the mechanism, not just to the effect.
- Rank your factors, do not list them. Accessibility is strongest, because every departure from the trend occurs at a junction; land value is second, because it explains the type of retail at each peak but not its location. Ranking with a reason is a Merit move that costs one sentence.
Where the factors come from, and how to evidence them
- Elements — your own map, aerial imagery, the council's district plan.
- Processes — data at two or more dates. A process cannot be evidenced from one snapshot, because a process is a change.
- Events — council minutes, local news archives, the date on a building consent.
- Perceptions — your own survey or interviews. Report the sample size and the question you asked, or the result cannot be judged.
- Everything gets a source and a date. Undated evidence is the commonest weakness in an internal.
Worked Example
Worked example
A student has to explain why the Rangiora Road big-box strip in the invented city of Tawharau is where it is. They write:
The big-box strip is on the ring road because there is lots of land there and it is easy to get to. Also land is cheaper on the edge of cities.
Turn this into a Merit-level explanation using the four kinds of factor.
Answer:
Step 1 — sort what they already have. Lots of land is an element; easy to get to is one too, but too vague to check. Land is cheaper on the edge is a general truth about cities and fails the "does it vary?" test — the whole edge is cheap, and the strip occupies one small part of it.
Step 2 — make the element specific and quantified.
The site is the junction of the ring road and the eastern arterial, the only point in Tawharau where two roads each carrying over 20,000 vehicles a day cross, with 31 hectares of former rail-yard land — the largest flat block inside the ring road.
Step 3 — add the mechanism, which is what was missing.
A bulky-goods store draws its customers by driving time, not by walking distance, so its trade area is set by how many vehicles pass and how easily they can turn in. That is why these stores locate at junctions rather than simply on cheap land: cheap land 3 km further out with 4,000 vehicles a day would have a fraction of the catchment.
Step 4 — add an event, because events give you dates.
The strip did not appear gradually. The rail yard closed in 2003, the council rezoned the block to Large Format Retail in 2006, and five of the eight stores opened between 2007 and 2011. The rezoning is the factor without which the other factors could not act — the land was equally cheap and equally accessible in 2002, and nothing was built.
Step 5 — add a perception, because it is in the standard and it changes the answer.
A survey of 60 shoppers found 68 per cent believed CBD parking was difficult, while the council's count showed occupancy peaking at 81 per cent — spaces were available. The belief, not the parking, is doing the work: shoppers avoided a difficulty that largely was not there, and retailers followed the shoppers.
Step 6 — rank the factors and name a limit.
The rezoning event is strongest, because the site's other advantages existed for years and produced nothing. Accessibility is second: it explains why this junction rather than another rezoned site. Perception of CBD parking explains why the demand existed, but not the location, since it applies equally to any out-of-centre site.