Net Promoter Score

A pure clojure library for generating Net Promoter Score values

Add this project via Leiningen/Boot:

[net_promoter_score "1.0.0"]

Add this project via deps.edn:

net_promoter_score {:mvn/version "1.0.0"}

Gradle: compile 'net_promoter_score:net_promoter_score:1.0.0'

Maven:

<dependency>
  <groupId>net_promoter_score</groupId>
  <artifactId>net_promoter_score</artifactId>
  <version>1.0.0</version>
</dependency>

---

Usage:

The main functionality of this library is exposed via the net_promoter_score.core namespace. Pulling that into your code is simple:

(:require [net-promoter-score.core :as nps])

Getting a Net Promoter Score

If you only need to retrieve a score for a list of numbers, you can pass all of the values to the get-promoter-score function inside a vector. This will, by default, use the 6/9 cutoffs that are used for sttandard NPS calculations.

(nps/get-promoter-score [1 2 3 4 5 6 7 8 9 10])
=> -40

If, for some reason, you need to use custom values for your promoter/passive/detractor calculations (maybe your marketing team wants to feel better about themselves?) You can pass min/max values to get-promoter-score in order to reconfigure how it will calculate your NPS.

(nps/get-promoter-score [1 2 3 4 5 6 7 8 9 10] 4 7)
=> 0

get-promoter-score does validate your inputs to make sure that they're within the 0-10 range that's standard for NPS scores. This can't be reconfigured.

(nps/get-promoter-score [11 -1])
=> AssertionError

get-promoter-score will provide back a soft warning that your calculations are invalid if you provide an empty vector.

(nps/get-promoter-score [])
=> "N/A"

Getting a statistical summary of a set of scores

If you'd like to dig a little deeper into your NPS values, picking up information about the mean, median and standard deviation of your scores, get-promoter-summary should suit your needs. It behaves similarly to get-promoter score, so to retrieve a summary of a vector of values:

(nps/get-promoter-summary [1 2 3 4 5 6 7 8 9 10])
=> {:score -40 :mean 5.5 :median 5.5 :standard-deviation 2.8722813232690143}

Setting custom boundaries for that same vector:

(nps/get-promoter-summary [1 2 3 4 5 6 7 8 9 10] 4 7)
=> {:score 0 :mean 5.5 :median 5.5 :standard-deviation 2.8722813232690143}

Errors when provided invalid values

(nps/get-promoter-summary [11 -1])
=> AssertionError

Soft warnings when provided an empty vector:

(nps/get-promoter-summary [])
=> {:score "N/A" :mean "N/A" :median "N/A" :standard-deviation "N/A"}

Getting a statistical summary of a set of scores based on the date those scores were entered.

If you need to slice your data based on time windows, get-promoter-summary-with-dates provides visibility into the statistical nature of your Net Promoter Score entries for the following time periods:

• All Time (The full population provided)
• The last 7 days, today inclusive
• The last 30 days, today inclusive
• 30-60 days ago
• 60-90 days ago

get-promoter-summary-with-dates does not take a vector of scores, but instead takes a vector of hashmaps with keys of :score and :date. :score should be an integer representing a NPS score (0-10). :date should be either a string representation of a date (default formatting is yyyy-MM-dd or a java.time.LocalDate object).

The API of get-promoter-summary-with-dates conforms to the same specifications of inputs and outputs as get-promoter-summary. It returns a series of 5 summary hashmaps identical to the output of get-promoter-summary for the specific windows as listed above.

Getting summaries for a list of values with dates:

(nps/get-promoter-summary-with-dates [{:score 1 :date ...}])
=> {:all-time {...} :last-seven {...} :last-thirty {...} :thirty-to-sixty {...} :sixty-to-ninety {...} }

It validates inputs as expected, will return "N/A" for time periods with no entries, etc.