Dec
2020

Oxford-AstraZeneca Vaccine: Why the Uncertainty?

The preliminary results from phase III trials of COVID-19 vaccines have been reported in the media. The vaccine developed and trialled by Pfizer and BioNTech is reported to be 95% effective and Moderna's is 94.5% effective. Trial results of the vaccine being developed by Oxford University and AstraZeneca show that it is 70% effective, but "with potential for that to rise to 90 per cent". In this blog we explore the reasons and implications of this uncertainty.

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Nov
2020

COVID-19 Vaccines: What Does 90% Effective Mean?

In the past few weeks, we’ve heard from multiple pharmaceutical companies that interim results of their Covid-19 vaccines are showing surprisingly good results. But what does 90% effective actually mean? How do we know what percentage of a population a vaccine is able to protect when we don’t know how many people may have been exposed to the virus?

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Feb
2016

Sensitivity, Specificity and Predictive Values – What is the best way to measure the performance of binary classification models?

Classification means assigning an outcome to an individual or case, usually for the purpose of making a decision. Examples include predicting which individuals will default on personal debt to decide who could be offered a credit card, or predicting which visitors to a retail website will make a purchase. In this blog we will discuss some ways of measuring the performance of a classification model.

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Jul
2015

Classifying Binary Outcomes

We recently discussed how a logistic regression can be used to model a binary response and predict the probability of a binary outcome. However, there are instances when we need to take this a step further and classify the outcome based on a cut-off probability threshold.

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Jun
2011

Statisticians Are Key to Business Growth and Innovation

Analysing large data sets will become a key basis of competition, says a new report published last week. In the same way that they have always sought professional accounting and legal advice, many industries now see statistical consultancy firms as crucial partners in driving growth and stimulating innovation.

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