# ipsos-credibility-interval¶

A Python tool that calculates Bayesian credibility intervals for online polling using the Ipsos method

The Ipsos credibility interval is a Bayesian metric that can be used to calculate the margin of error. It estimates accuracy plus or minus a number of percentage points. You can learn more by reading the Ipsos white paper.

## Installation¶

The package is available in the Python Package Index. You can install it with pipenv or another package manager.

```
pipenv install ipsos-credibility-interval
```

## Usage¶

To get an estimate, you must import the library and provide the sample size to the `get`

function. It will return the credibility interval in percentage points. Here’s an example with a sample size of 1,000:

```
import ipsos_credibility_interval
ipsos_credibility_interval.get(1000)
3.5333753221609374
```

You can provide a custom confidence level. The default is 95%. This would return the interval for a 99% confidence level:

```
ipsos_credibility_interval.get(1000, confidence_level=0.99)
4.643642315394128
```

You can also customize the weighting factor designed by Ipsos. The default is 1.3. This example would return the interval for a weighting factor of 1.5:

```
ipsos_credibility_interval.get(1000, weight=1.5)
3.7954539356449795
```