Since it was launched in 2003, the Net Promoter Score (NPS) has been a sensation in consumer research. As a metric based on a single question, some have claimed it to be an ultimate indicator, although doubts have been raised about its efficacy. In 2016, more than two thirds of the USA’s fortune 1000 companies used it.
The Employee Net Promoter Score (eNPS) is a variant of the basic NPS, said to evaluate employee engagement. It asks only one question to gauge whether employees would recommend their place of work as a good place to work. Many companies now rely on it as a primary metric for their employee research.
But, is the simplicity of a single-question metric worthwhile? Is it good business to rely on these single-question methods?
It sure is easy
Simplicity is great and a single question only takes a second.
So sure, we support the use of well-crafted questions like these. We just don't recommend it as the only question to ask.
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Is it the ultimate?
Studies have shown that other single-item measures might be just as good as the NPS method. In some cases, similar tools may actually produce better results.
In general, statisticians agree that well-constructed multiple-item indicators are more reliable and tend to provide better external validity than single-question metrics. There are many employee engagement indexes that do just that.
Testing eNPS and engagement
We're always keen to test things out using our own data. So, we decided to test an eNPS-type score against a multi-item indicator—Culture Amp’s Engagement Index.
We conducted research with a customer where we had about 500 people use a 0-10 eNPS question as well as our standard 5-point question. The results were close to perfectly the same with a correlation of .91 and the 0-10 and 5-point eNPS scores were both around 37 (decimals apart at 36.6 and 36.7 in this case). Here's what the data looks like.
This image is a smoothed density scatterplot of eNPS scores using 5-point and 0-10 (11-point) scales. The regression line shows a near perfect correlation (r=.91). N.B. Darker zones represent larger numbers of respondents in the same spot on the chart.
How useable information differs
On average, eNPS scores seem to be strongly related to the other things Culture Amp asks for in its Engagement Index. The connection of eNPS with pride, motivation and commitment is evident, but it is not strict. For some organizations, the results obtained by using each method were significantly different.
Some of the organizations rank more highly on an eNPS metric than they do if they use the more comprehensive engagement metric. At the employee level, this may mean that some employees are prepared to recommend their company even though they lack motivation or do not feel engaged as an individual.
The only way to detect these irregularities is to ask more than one question.
How much information do I really need?
You don’t want reams of reports. You just need to make sure that the information you rely on accurately reflects the reality of your situation.
If your organization is one of those that strictly adheres to the correlation, that’s great. If it’s one of the one that deviates, you’re probably going to want extra info to be sure you know what you’re dealing with. How would you know whether your company adheres? Put simply, the only way to know is to ask more employee engagement questions.
What about those who use the single-question metric?
Many of the organizations that rely on the eNPS seem to be tracking fine. They work with their employees to maintain their scores. I think this stands testament to the fundamental importance of measuring simply and regularly and checking in with employees.
The fact that eNPS seems okay most of the time does not mean that it is the ultimate question. It just shows that doing something about engagement is definitely worthwhile. Of course, doing something is a great start. Doing it better is the way to amplify your positive outcomes.
So, what should you do?
The simplicity of a single-question metric certainly has its appeal. If you are limited to asking just one question, an eNPS score might be a great question to ask. However, for some purposes there are others questions that might be better. In most situations, asking more than one question will increase accuracy.
Simplicity is great, but so is accurate and reliable information. While one question only takes a second, a couple of extra questions only takes a few more seconds.
If your employees can spare a minute or two, ask two or three other types of engagement questions as well. It’s easy and efficient and it will give you a broader and more statistically reliable metric.
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