Keep It Clean:  Why Data Hygiene Is So Important

data hygiene

data hygiene

Marketing Executive

I create content, publications and adverts for Wired Plus.  When I’m not writing, reading or blogging I enjoy road running.


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Data Hygiene For Email Marketing

Data Hygiene is essential to the success of email marketing campaigns.  In this article, we discuss data hygiene, the impact data hygiene has on your email campaigns and ways to improve your processes in the future.What is Data Hygiene?

Data Hygiene concerns the processes that companies undertake to check the quality and validity of contact information they hold.  These actions should be performed on a regular basis to ensure list quality is maintained over time.  All companies should have some way to monitor the quality of their data no matter how large or small their contact database.

Creating the perfect email with an eye-catching layout and convincing copy will have no effect if your email doesn’t reach the right contacts.  The issue of hygiene is more pertinent now than it ever has been due to the imminent arrival of the General Data Protection Regulations (GDPR).

Consistent data hygiene routines are more likely to result in stable campaign performance over time.  Consider how many systems you have and how they interact with each other; data which is duplicated across systems should be automatically updated together to prevent inconsistencies arising over time.

Why is Data Hygiene Important?
Your Reputation

Your sender score is calculated based on factors including: The number of spam complaints you receive, the volume of emails you send, whether you send emails to addresses marked as spam by Internet Service Providers and the percentage of unknown users you contact.  Each of these factors is impacted by the data processes that you have in place to clean your email list.

Poor data hygiene negatively impacts your sender score as spam complaints, spam accounts and unknown users all detract from your email campaign performance.  It is important to note that just because somebody wants to be added to the list does not mean they will want to stay there long term.  As a result, users should be given a clear and easy way to unsubscribe.

Campaign Results

Good data hygiene practices are reflected by good campaign results.  Although data hygiene is not the sole reason for a successful campaign, it is a significant factor in campaign performance.  There are a number of email campaign metrics that you can analyse to monitor whether your practices are working.

As your sender reputation is likely to improve after implementing good data hygiene practices, the percentage of emails which are delivered will also increase, improving your overall campaign performance.

Email open rates will improve as you remove any spam or inactive accounts from your contact database.  As your open rates are calculated based on the number of emails that you send, rather than as a percentage of emails which are received by your contacts, scrubbing your list of such accounts will improve your results.  Gathering contact details through double opt-in data collection methods provides you with the assurance that your subscribers want to hear from you.

Quickly removing any contacts who have chosen to unsubscribe from your emails decreases the likelihood that they will mark you as spam.  By removing unsubscribed contacts you are also decreasing the number of emotionally disengaged users from your contact database, improving the percentage of users who are likely to open and take action on your email.

Discovering Errors

Data hygiene is a good opportunity to spot any erroneous data that may have entered the system at the input stage.  Although data may have been collected from a genuine customer or prospect, occasionally human error may cause errors in the data.

Customer data may contain spelling mistakes or be formatted incorrectly rendering it unusable.  In these cases, although the data has come from a legitimate source, it is still detrimental to the email marketing campaign.

Many errors in data sets are caused by not standardising certain types of data. For example, how many ways are there to input the word “street”?  Street, STR, Str. Str. street….. What about potential spelling mistakes too?

This can easily be solved by using dropdowns during data input which limit the formatting to approved guidelines.

Improving Your Data Hygiene

Data hygiene does not just concern data that you have previously collected. Establishing good data hygiene routines will impact the data that you collect in the future.  Following the advice below, you can spot then rectify or remove poor quality data and ensure that any future data is error-free.

List Scrubbing

It is imperative for companies to perform regular contact list scrubbing to ensure that data is both accurate and up to date.  Remove any emails which have hard bounced, indicating that there is a problem with the data quality for that contact. You should also ensure that you remove emails which belong to individuals who have unsubscribed from your communications.  These should both be done immediately.

Cleansing the remaining data should be done on a regular schedule, based on how often you contact the contact lists.

Purchased Lists

When purchasing data from another company, there is no way to check that the data has come from a legitimate source.  Data is out of the control of the marketing agency and should not be used for email marketing campaigns in the future. Purchased lists are unlikely to be compliant with GDPR which come into effect in May 2018. This is all down to the fact that bought data lists won’t have opted in to receive communications from you.

Bad Domains

Pay close attention to the domain field on your contact record.  If your domain is incorrect or does not exist it should be edited or removed from your system.  In instances where the domain is simply misspelled ‘htmail’ or ‘hayoo’, these fields can be amended and re-added to the system.

Inactive Accounts

Sending emails to accounts which are no longer active, either because the company no longer exists or because they have created a new account, will negatively affect your reputation.  Monitor your analytics to identify which clients are engaged and active when they receive your campaigns.  Before removing a seemingly inactive account from your system, it might be worth sending one last email to double check whether the account is inactive or whether they have simply not engaged with you for a while.  Once you have identified an inactive account on your list, remove it.

Feedback Loops

When you are building up your email list, set up feedback loops so that you can remove any subscribers who no longer want to receive your communications.  A feedback loop will notify you when a user has clicked on the ‘unsubscribe’ link in your email. For companies using email service providers, this will have already been set up for you.

Validity Check

When you are collecting data, check the validity of the data that users are entering into your system.  You can set up data validators to capture basic errors such as incorrect data type entries and unknown email addresses, you can then give the user the option to amend their data before they submit it.

Hard Bounces

The ‘hard bounce’ field in your email analytics shows any emails that have bounced due to a permanent error.  This error may be caused by a non-existent domain or when the recipient of the email is unknown.  Any emails that have hard bounced should be removed immediately from the email list to prevent any negative impact on the sender’s reputation and campaign results.


Engagement with email campaigns deteriorates over time.  When contacts become disengaged with your email campaigns, you should remove them from your database.  Sending emails to people who no longer action, read or even open them is a waste of time and budget.  When you have identified a disengaged contact, try to re-engage them , but if re-engagement fails, remove the contact from your list.

Renew Customer Data

Be aware that a contact’s details are likely to change over time.  Just as people get married and change their address, they are also likely to change their email address too.  At the point of collection, data is the most up-to-date and accurate that it is going to be.  Customers should have a simple way to alert the company if their email address or any other personal data needs to be updated.  Companies can periodically prompt customers to enter a form to confirm whether any of their personal data should be updated.

Suppress Unsubscribers

Companies should place anybody who has unsubscribed from email campaigns into a suppression list rather than deleting their details.  This ensures that you do not send emails to the unsubscribed contact in the future. Keeping a list of people who shouldn’t be sent communications gives you a reference in case they do re-subscribe later.


Good data hygiene practices are vital to email marketing success. If you don’t have accurate data you are running the risk of ineffective segmentation, poor contact experience, low delivery rates, and decreased ROI.

These practices aren’t difficult to do and don’t take up much of your time, but they do have a massive impact on your email marketing effectiveness.

Ultimate Email Guide

Marketing Executive

I create content, publications and adverts for Wired Plus.  When I’m not writing, reading or blogging I enjoy road running.

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