The document discusses the importance of email validation for improving deliverability and marketing results, emphasizing that sender reputation significantly affects email performance and inbox placement. It highlights key metrics like bounce rates and complaint rates that contribute to sender reputation and outlines how email validation tools can help to identify undeliverable addresses, spam traps, and high-risk emails. By implementing effective email validation practices, marketers can enhance their email campaign success, reduce costs, and ultimately achieve better returns on investment.

1. EmailValidation for Improved
Deliverability and Marketing Results
An Experian QASWhite Paper

2. EmailValidation: How to Improve
Deliverability and Marketing Results
Reduced inbox delivery and
performance
Internet Service Providers (ISPs)
like AOL, Hotmail and Gmail actively
screen and filter incoming mail for
their users. Increasingly, ISPs rely on
a mailer’s “reputation” to determine
what email messages will get through
to users’ inboxes. In fact, a study
by Return Path found that 77% of
delivery problems were based on
sender reputation. Sender reputation
is based on several factors:
Bounce rate- the number of
messages that are returned as
undeliverable divided by the number
of emails sent.
Complaint rate- the number of people
who report your messages as spam
divided by the number of emails
delivered.
Spam trap hits- the number of emails
delivered to addresses that are
explicitly used to trace and catalog
spam.
With all of these metrics, the higher
the numbers are, the worse the
sender reputation. A slightly poor
reputation will cause some messages
to go into the spam folder, and, as
reputation worsens, messages may
be partially or fully blocked.With
AOL, for example, a complaint rate
over 0.1% may cause some messages
to go into the spam folder, and a rate
over 0.3% may lead to messages
being blocked.
For most ISPs, a double digit bounce
rate or mailing to a single spam
trap can lead to some blocking.
Once sender’s reputation has been
damaged, it takes time and effort
to return to a positive relationship
with the ISP.This means that while
messages in the current campaign
receive less-than-desirable inbox
placement, future email campaigns
may also be negatively impacted.
Email marketers looking to improve
and/or maintain positive reputation,
to ultimately improve marketing
results should evaluate potential
email validation tools to improve the
quality of email lists.
Improved reputation and results
Email validation starts with the
identification of undeliverable email
addresses, but more comprehensive
validation services can also flag
spam traps and addresses that are
likely to generate complaints. A full
suite of validation services leads to:
• Reduced bounce rate-Removing
Email is quickly becoming the preferred method of communication for businesses across the
world, regardless of industry. Email is faster and less expensive than traditional mail, and many
customers choose to receive messages from the companies they do business with through the
email channel.
The success of your email marketing program depends on your subscribers seeing and responding
to the messages you send. Effort spent optimizing the content, relevance, and timing of emails
is wasted if subscribers never actually see these communications. Getting email messages into
the inbox is essential for email marketing success, and mailing to undeliverable emails, people
who will mark your messages as spam (a.k.a. complainers and screamers), and spam traps can
cause emails to be lost in the spam folder or even blocked. Email validation tools enable you to
prevent bad addresses from permeating your list, improve deliverability, and capture more leads –
ultimately leading to stronger ROI on email communications.

3. invalid email addresses from your list or preventing them
from getting onto the list in the first place means that a
greater percentage of emails sent will be delivered.
• Fewer complaints and spam trap hits- Not mailing
to people who will mark your messages as spam and
avoiding traps results in a lower complaint rate and a
better sender reputation.
• Increased inbox delivery and results-With a better
reputation from fewer bounces and complaints, more–
if not all-messages will make it into the inbox of your
subscribers, resulting in greater open, click, and response
rates.
• Lower mailing costs- If you use an Email Service
Provider (ESP) to send email, fewer messages sent
translates to lower costs. Improved deliverability
also means less effort managing your mailings and
infrastructure.
• More usable leads- Validating emails when they’re
entered on your website ensures that you capture a
working address, increasing data quality and the number
of deliverable addresses on your list.
After implementing email validation, companies have
reported as much as a 75% reduction in bounce rates and
20% growth in open rates. For a retailer, higher open rates
mean additional sales that directly benefit the bottom
line. For email newsletters, more opens result in greater
brand exposure and better response rates to ads, thus
repeat advertisers and higher advertising rates.
Validating emails at the point of entry online reduces data
entry errors and fraud, resulting in fewer lost leads and
a larger email list. In an analysis of real-time validation
results across its clients, Experian QAS has found that as
much as 8% of emails entered on websites are incorrect
or invalid. If you pay a penny every time you validate an
email, catching bad emails and capturing good ones has
a positive ROI if the lifetime value of an email address
is at least $0.125. For businesses that measure the value
of an email in dollars, money is clearly being lost if email
validation has not been implemented.
How to validate email addresses
Email validation can be as simple as checking if there is
an ‘@’ sign in the address. But to achieve the cleanest
and most mailable set of email addresses, there are
several steps that should be performed.
Catch and correct syntax errors
The proper syntax for email addresses is defined by the
Internet standards document RFC 5322, yet it is important
to note that there are some email address formats that
are used in practice that do not meet the standard. For
example, the RFC prohibits the use of a period before
the ‘@’ symbol, but some domains allow it. It is therefore

4. essential to use a validation tool that is sophisticated
enough to both accept the full range of valid email
addresses and also catch emails that on the surface look
acceptable, yet in fact will never work.
Free email validation programs do a relatively simple
series of checks to see if there is a single ‘@’ and a period
in the domain, and ensure that the email as a whole uses
an accepted range of characters. Often, these free scripts
permit emails with syntax errors, but also reject perfectly
valid ones, leading to lost customers. For example, certain
web forms will not accept emails that contain a plus sign,
even though domains such as Gmail permit these email
addresses. However, a plus sign cannot be used in a
domain name, and other validation programs will let this
through.
Most ISPs enforce their own format rules, which are
stricter than the overall standard. For example, AOL
email addresses never start with a number, and a plus
sign cannot be used in a Hotmail address. By using email
verification that incorporates accurate ISP format rules,
you can minimize bad data and capture more valid emails.
By correcting email addresses with syntax and spelling
errors, you can recover otherwise invalid emails and
assist visitors to your website. Email syntax errors
can appear because addresses were mistyped by
customers online, improperly entered by customer
service representatives, or incorrectly scanned from
product registration cards. Domains could be misspelled,
someone might type ‘2’ instead of ‘@’, or a comma appear
used instead of a period. Advanced email validation
solutions can fix these errors, allowing the sender to
either prompt a customer with a suggested correction or
update the email list prior to the next mailing. Here are
some examples:
Invalid Email
“Smith, Bessie” <bsmith@
example.com>
fred;billings!@netzreo.net
john_doe2hotmale.com
steve@atntworldnet.com
joseaol.com
Corrected Email
bsmith@example.com
fred.billings@netzero.net
john_doe@hotmail.com
steve@worldnetatt.net
jose@aol.com

5. Confirm email domains work
Properly validating email domain names–the portion of
the email to the right of the ‘@’ sign-further increases
the number of addresses flagged as invalid. For many
lists, proper domain validation can find three times more
“dead” emails than syntax checks alone.
A valid domain both exists and is enabled to accept email.
Many domains have been registered, but email servers
have never been set up, so these domains cannot accept
mail. However, email marketers are cautioned not to rely
on solutions that verify domains in real time. Network
outages are a fact of life on the Internet. If there was any
network interruption during a real-time domain check, all
addresses at that domain would be falsely categorized as
“dead.”
Enterprise validation services maintain a domain
database and monitor the status of a domain over days,
not seconds. A domain is classified as invalid only if it
fails repeated checks over several days, which ensures
that no valuable data is lost.
Verify mailboxes exist
The most important component of email validation is
verifying the mailbox at the domain. For example, with the
address sarah667@hotmail.com, is sarah667 a working
account at Hotmail? Experian QAS has typically found
that invalid mailboxes consistently account for over 70%
of the undeliverable emails found during email validation.
The most accurate way to validate a mailbox without
actually sending an email message is to “ping” the
mailbox.This is done by pretending to send to an address
without actually doing so. It uses the same process as
email delivery software to check for a hard bounce, and
it can be just as accurate, as long as the solution can
accurately differentiate the myriad status codes returned
by email servers.
It is important to note that this is not a process that can
be carried out by any organization. Pinging a domain
many times without actually sending any email can cause
an IP address to be blocked. Using an email validation
provider who uses their own dedicated IPs and conforms
to best practices will insulate you entirely from any risks.
Mailbox pinging will find most, but not all, undeliverable
emails.The administrators of each domain control
whether the domain will provide hard bounce information
during an email delivery session (using the SMTP
protocol).While the majority does this, some domains use
catch-all accounts and never generate a single bounce,
and some domains only send a bounce email if an email is
actually sent.
Suppress spam traps and risky email addresses
Emailing certain kinds of addresses can hurt your
reputation and ability to communicate with subscribers.
Here is a description of each kind and how you should
handle them:
Types of spam traps
Spam traps are working email addresses that are used
to identify spam messages and senders of spam. Mailing
to them can get you blacklisted and blocked. Because
spam traps are supposedly never actively subscribed to a
mailing list, the reasoning is that any email sent to them
must be unsolicited, i.e. spam.
Traps may appear on your email list as a result of
abandoned emails, malicious activity, or harvested data.
Old, once valid emails are sometimes converted into
spam traps. Someone could deliberately poison a list by
subscribing a known spam trap to it. Emails harvested
from the Internet frequently contain spam traps, and data
should never be purchased from a disreputable source.
The creators of spam traps do not want them to be
discovered, so it is impossible to build a comprehensive
list of these damaging addresses. However, by working
with a validation provider that has a long history in the
industry, you can minimize the risk. Its important to be
aware of the following types of spam traps:
Role-based accounts
Mailing email addresses that represent a group of people
or a job function such as sales@domain.com or info@
domain.com is not recommended. Because multiple
people frequently receive messages sent to such
accounts, those messages are more likely to be marked
as spam. In addition, role-based email addresses for old
domains are more likely to be repurposed as spam traps.
Fake emails
While not nearly as harmful as the categories above,
allowing fake addresses onto your list ties up resources
and allows people access to information you wanted to
protect. Fake addresses can be as simple as asdf@asdf.
com or contain vulgar words. Using the proper email
validation on a web form will stop a list from being
polluted.
Complainers and screamers
Within the email industry, “complainers” are people
who habitually report commercial email as spam, and
“screamers” are the dreaded individuals who angrily call
to complain about unwanted email and sometimes even
threaten to sue.When working with a large or historical
email list, it is better to be safe than sorry and weed out
addresses that may increase your complaint rate, ruin
your mailing reputation, and cause your messages to be
filtered or blocked.

6. Known bouncers
While real-time mailbox validation is highly accurate,
it is a resource-intensive process and may not be cost-
effective for large email databases. A quicker and more
affordable solution for reducing your bounce rate is to
match your list to a file of emails that are known to have
bounced when mailed. Any company that does large
volume email delivery maintains such a list, and some
email validation providers aggregate this data and offer
it as a service. It is important, however, to use only lists
that are recent and were collected using accurate bounce
tracking technology.
All known bouncer lists suffer from false positives, i.e.,
they incorrectly contain some working email addresses,
and the problem gets worse with older lists.When
working with bounce suppression, you should be wary of
match rates that are too high.You can test the vendor’s
bounce list against emails you’ve recently mailed to see
how many deliverable emails were improperly flagged
as dead. Depending on the size of the subscriber list,
the value of an email address for your business, and your
specific deliverability challenge, a bounce suppression
file can either quickly ready your list for mailing or cause
more problems than you had anticipated.
Do Not Mail
The Direct Marketing Association maintains a list of
people who have contacted the DMA and asked to not
to receive unsolicited commercial email. By matching
prospect email lists against the DMA file, you can avoid
complaints and support industry efforts to reduce spam
and avoid legislation.
Wireless domains
As part of the federal CAN-SPAM legislation, sending
unwanted commercial email messages to wireless
devices without prior permission is against the law.
The FCC maintains a list of Internet domain names
that are used to transmit email to wireless devices, and
prospect lists should be matched against the list to avoid
complaints and fines.
When to use email validation
There are a variety of tactics for keeping your email list
clean, but when should you use them?
At the point of entry
Validating email addresses as they are collected is the
best way to prevent bad emails from getting on your list.
In addition, by prompting users as they enter invalid
emails, you can increase the number of working addresses
added to your list, which translates to increased revenue
and brand awareness.
Emails actively submitted to your list are fresh, and those
customers have a confirmed interest in subscribing. In
this setting, the best validation techniques are:
• Syntax, domain, and mailbox validation
• Email correction
• Suppression of spam traps, role-based accounts, and
fake emails
Prior to mailing dormant data
If you have an email list that has not been mailed in
months or years, scrubbing it before mailing it will greatly
increase the chance that you will be able to successfully
deliver emails to those subscribers. Some ESPs shut
down mailings that exceed their thresholds for bounce
and complaint rates, and only by validating the list first
will you be able to use it.
All of the tactics reviewed in this white paper are relevant
to email data that hasn’t been recently mailed, and, for
very old or large lists, suppressing known bouncers and
complainers can be a very effective and low-cost way to
avoid damaging to your sender reputation.
For regular email hygiene
Once you’ve cleaned your house list and are checking
emails as they come in, validating unmailed addresses
on a quarterly or semi-annual basis will keep your list
in optimal condition and ready for mailing. As dead
addresses are removed from your list, consider an Email
Change of Address (ECOA) service to replace abandoned
email addresses with the current addresses of your
subscribers.
How to use emailvalidation
EmailValidation can be accessed in any of three methods:
• In Real-Time- Using an API or web service is the best
tool for validating email addresses on a website, mobile
device, or anywhere an individual email address needs
to be checked instantly. Choose an API that has all the
functionality you require, is easy to integrate, and has a
reputation for reliability.
• In Batch-The batch process is the simplest validation
method with limited requirements. It is best suited for
companies with occasional projects, limited database
administration resources, or that do not have a sense of
urgency. Depending on the size of the file, the lead-time is
typically 2- 5 business days.
• Automated Batch- For frequent submission of email
lists, batch processing can be automated using FTP file
delivery and file naming and format conventions. Files are
detected and submitted for processing every few minutes
and results are ready for retrieval within hours. Retailers
who collect data from their stores nightly, for example,
use automated batch processing to validate and correct
data the day it was collected, prior to integrating it into
their central database.

7. Experian QAS
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Boston, MA 02110-1615
T: 1 888 322 6201
info@qas.com
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Conclusion
Deliverability is an essential component of email
marketing success. By consistently and thoroughly
validating the emails on your list, you can keep it clean
and improve your sender reputation. A cleaner email list
will deliver to inboxes more frequently. Improved inbox
placement means more opens and clicks, and ultimately,
better marketing results. Email validation is a fast,
easy-to-use, and cost-effective solution for significantly
boosting the performance of your email marketing and
communication programs.
Experian QAS Products and Services
Experian QAS provides software and services to capture,
validate, cleanse, standardize and enrich customer
contact information. We are dedicated to helping our
11,000 customers worldwide improve the quality of their
databases. For more information visit our website at www.
qas.com or call us at 1-888-322-6201.
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