Email Verification & Validation

Published October 27, 2015 03:23:10 PM  |  Last update October 29, 2015 10:55:34 PM

Email verification and validation are among the essential issues in business intelligence. While the former is based on technical specification and can be done using some technical methods, the latter is more complex and should be done using some advanced techniques, which are mainly from information retrieval and machine learning research areas, based on data quality attributes defined by business requirements.

Verification vs. Validation In software engineering, the Verification and Validation process (V&V) is used to assure the quality of all products in various stages of the software development lifecycle. Verification and Validation describe different procedures and it is necessary not to confuse of these two terms. Validation is a process that assures “we built the right thing” while verification is to assure “we built that thing right”. In other word, verification confirms whether a product complies with the specification while validation with the needs. Validation results in a subsets of verification. It is therefore usually done after the verification.

  • ISO/IEC 12207 VALIDATION: "Confirmation by examination and provisions of objective evidence that the particular requirements for a specific intended use are fulfilled."
  • ISO/IEC 12207 VERIFICATION: "Confirmation by examination and provisions of objective evidence that specified requirements have been fulfilled."

Email verification Email verification takes into account the two parts of email address, the local part which is the portion standing before the ‘@’ sign and the domain part which is the email domain name. The ideal approach is to check email against the email list of the mail provider. This email list however does not exist. Hence, common approach for email verification is to check the two parts of an email, whether they comply with the email structure standard. A simple regular expression based verification method is shown, below:

$email = “an-email”;
$regex = '/([a-z0-9_]+|[a-z0-9_]+\.[a-z0-9_]+)@(([a-z0-9]|[a-z0-9]+\.[a-z0-9]+)+\.([a-z]{2,4}))/i';
$isValid = preg_match($regex, $email);

Email validation Validation of an email to assure that the email meets some requirements. Email requirements are different from application to application; for example, Email Marketing (EM) and Customer Relationship Management (CRM), both use email address for messages delivery, their requirements however are different: EM requires emails to be potential for revenue purpose while CRM just needs emails for sending message to its users. Email validation are particularly difficult if techniques used are not precise or requirements are not easily convertible to validation measures. Those make validation techniques unable to give a definite answer and end up yielding only a probabilistic assurance of the email quality. Since it is possible to make a wrong decision about that, it is necessary to understand how likely such mistakes happen. These classification mistakes are twofold, invalid data are treated as valid and valid data are treated as invalid. Analogically to a hypothesis testing makes possible definition of misclassification probability. Send message to an invalid email address will affect the sender reputation and also have impact on the network and SMTP server utilization. Selected techniques should yield significantly low probabilities of making mistakes.

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