IA idea · Statistics & hypothesis testing

How much is being near a station worth?

AI SLAI HLAA SL Solid Also in: Finance, Geometry & Voronoi

Research question

In [a town], how strongly is the sale price of similar houses related to their walking distance from the nearest railway station, and what is the estimated price change per extra kilometre?

Adapt it: change the place, the data or the comparison until the question is yours.

Why it makes a good exploration

Estate agents say transport links add value. Using official sale prices and map distances, you can put a number on it — and discover how many other variables get in the way.

The mathematics you'll need

Scatter plots, correlation and linear regression
Interpreting the gradient in context
Spearman's rank for non-linear relationships
Residual analysis to find unusual properties

Course labels show where a technique sits; using maths from outside your course is fine if you explain it clearly and say it is new to you.

Where the data comes from

Take 40+ sales of one property type in one town from the Price Paid Data; measure distances to the station on OpenStreetMap.

HM Land Registry Price Paid Data — Every residential sale in England and Wales since 1995 (Open Government Licence).
OpenStreetMap — Free map with exact coordinates of schools, hospitals, shops and stations; export or read off coordinates.

Cite every source in a footnote where you use it and in your bibliography. Check the licence of any dataset you download.

A possible outline

Restrict to one property type and a narrow time window.
Measure distances consistently (walking route or straight line — justify).
Fit a regression and interpret the gradient.
Examine residuals for patterns (new builds, schools, flood zones).
Reflect on confounding variables.

Pitfalls that cost marks

Mixing flats and detached houses.
Using straight-line distance without justification.
Treating the gradient as causal.

Showing personal engagement

Choose your own town.
Compare two towns with different commuting patterns.
Estimate the value of your own street's location.

See Criterion C: personal engagement for what examiners look for.

Taking it further

Try a log-price model and compare with the linear one; discuss which gives a more sensible interpretation.

Turn this idea into your IA

Plan this IAOpens the planner with this question, the maths and data sources filled in. Desmos workspacePlot your data, fit models and keep your graphs with your plan. AI feedback on a draftCriterion-by-criterion feedback with evidence from your own text. Coaching, not rewriting. Examiner reviewPete, a practising IA examiner, reads your draft and talks it through with you (€100).