Analysing Disruptions

Overview

In this penultimate lesson of Mapping Data and Change, students investigate how an unusual event can affect a data set over time. They compare before-and-after patterns, identify anomalies, and communicate a conclusion supported by numerical and graphical evidence.

Learning intentions

• We are learning to identify patterns and unusual values in data collected over time.
• We are learning to compare data before and after a disruption.
• We are learning to use evidence from a graph or table to explain what may have happened.
• We are learning to communicate a statistical conclusion clearly and cautiously.

Success criteria

• I can describe the overall pattern in a time-series graph.
• I can identify an unusual value and explain why it may be an anomaly.
• I can compare data before and after an event using numbers.
• I can write a conclusion that uses evidence and acknowledges that data may not explain everything.

Curriculum links

• Mathematics and Statistics — Mathsteasers: higher-order thinking questions that challenge learners and deepen understanding.
• Mathematics and Statistics — Mathsteasers / Alignment: applying mathematical thinking to relevant textbook and classroom content.
• Mathematics and Statistics — Mathsteasers / Additional resources for advanced learners: extending capable learners through reasoning, investigation and explanation.
• Statistical investigation: noticing variation, interpreting data displays, and communicating a reasoned conclusion.

Lesson structure (45 minutes)

1. 0–5 min · Hook and prediction. Display the before-and-after comparison in the disruption hook slide: daily numbers of students using a school crossing over two weeks, with one day affected by heavy rain and a road closure. Ask, “What changed, and how confident can we be about the reason?” Students silently notice two features, then share a prediction with a partner.

2. 5–12 min · Teach the focus. Use the pattern and anomaly slides to review time on the horizontal axis, frequency on the vertical axis, overall trend, variation, and anomaly. Model thinking aloud: “The value on Wednesday is much lower than nearby values, so it is unusual; I need to check the event information before claiming why.” Students help distinguish an observation (“the number fell”) from an explanation (“the road closure caused the fall”).

3. 12–15 min · Model comparison language. Show the sentence frames on the evidence sentence slides and model a response using two data points from before and after the disruption. Students rehearse one comparison orally, using language such as “Before the disruption…”, “Afterwards…”, “The data suggests…”, and “However, we cannot be certain because…”.

4. 15–30 min · Paired investigation. Give each pair the disruption data investigation worksheet and distribute the line graph template pack. Students select the appropriate template, plot the supplied time-series data, mark the disruption, and answer the comparison questions. They identify the anomaly, calculate or describe the change using the values provided, and write a provisional conclusion. Teacher circulates, asking: “Which values are you comparing?”, “Is this a one-off value or a continuing pattern?”, and “What evidence supports your explanation?”

5. 30–38 min · Evidence conference. Pairs join another pair and use the partner-check slides to compare graphs and conclusions. Each student explains one pattern and one limitation in their partner’s work. Groups check that axes are labelled, the scale is sensible, the disruption is clearly marked, and the conclusion refers to actual data rather than guesswork.

6. 38–45 min · Share and exit assessment. Invite two or three pairs to present contrasting conclusions using the plenary slides. Finish with the final question on the worksheet: “Was the disruption the only possible reason for the change? Use two pieces of evidence.” Students submit their response as they leave.

Resources

• the disruption analysis slide deck
• the disruption data investigation worksheet
• the line graph template pack
• Pencils, rulers and coloured pencils
• Calculators, if required for checking differences
• Board or display screen
• Prepared example data showing daily values before, during and after a disruption

Assessment

• During modelling, listen for students distinguishing a description of data from a claim about causation.
• During paired work, check graphs for labelled axes, appropriate scale, accurate plotting, the marked disruption and evidence-based comparisons.
• Use the final written response to assess whether students can identify an anomaly, compare before and after data, and communicate a cautious conclusion.

Differentiation

• Provide a partially completed graph, a reduced number of data points, or a teacher-selected template for students who need support with plotting and scales.
• Offer sentence starters and a small word bank: pattern, variation, anomaly, before, after, evidence, suggests, possible reason, not certain.
• Pair students strategically and read the data aloud for learners who benefit from oral access; allow conclusions to be rehearsed verbally before writing.
• Challenge ready students to compare two possible explanations, calculate the size of the change in more than one way, or explain why one unusual value should not automatically be treated as a trend.