The modern legal professional is expected to handle large volumes of data that can exist in many different forms. One of these forms — and one of the most popular ways for companies to communicate with each other — is email, meaning evidence in emails is presented in almost every trial across the globe.

The average person receives over 100 emails a day, which can result in huge numbers of emails for legal review. Fortunately, there are analytics tools such as email threading that can help speed up and increase the accuracy of this process. 

In this blog post, we explore how email threading can significantly improve the effectiveness of a review without the hassle of manually reviewing a person's entire inbox.

What is email threading?

You've no doubt been involved in an email thread before. With the potential of several different people contributing to the discussion and documents being passed around, the data involved can stack up. The chronological collation and arrangement of these individual messages is called email threading.

Over time, as an individual partakes in more email threads, relevant information to a potential case can be swamped by the hundreds or thousands of emails a user sends or receives.

Email threading pulls together all connected documents - both emails and attachments - from an email chain. This allows you to easily locate other emails within the same thread coded as relevant, as well as identify any coding inconsistencies.

Analytics tools can speed up the review process when email chains are reviewed together in chronological order. This provides better context and understanding of the data, allowing the reviewer to identify relevant information faster.

How does this work?

With email threading, specialised tools analyse email subject lines, who the email is sent to and from, the date of sending and the email body to determine if an email belongs to a thread.

The emails are then arranged and grouped by their thread identification. For a thread identification to occur, a number of fields must be populated in one or more of the following:

• Sent date
• Email to
• Email subject
• Email Cc
• Email Bcc

If the document has any or all of the above aside from the 'sent date' field, it'll be categorised as a draft.

So, what steps need to be followed?

1. Emails are parsed into threads based on information populated in the Message ID (information about an email).
2. Metadata such as senders, recipients and dates are used to show thread branches, sort orders and email activity types.
3. Emails that belong to the same conversation are recognised and pulled together in an 'email thread group' using the body segments, email date, email to, email from and email subject data.

Now that you know what email threading is and how it works, let's look at how it can help with the eDiscovery process.

Email threading — A key eDiscovery tool

With the sheer number of emails being sent — a forecast of 347.3 billion per day in 2023 — litigation professionals will likely encounter cases that rely heavily on the information emails can provide.

It’s therefore not feasible for a reviewer to sit and comb through hundreds or even thousands of emails to extract the relevant data they need to support their case. But, with the help of eDiscovery software, email threading can produce the same results in a fraction of the time.

Email threading can significantly reduce the number of documents in a review queue by eliminating duplicate or irrelevant content and by presenting you with the most complete versions of an email thread. This cuts down the first-pass review time and increases accuracy, enabling a more considered second-pass review, and saving you time.

Not only this, but reviewing complete email threads will also help you better understand the context of all parties' communication and build your case. Furthermore, keeping emails and attachments grouped in chronological order helps a reviewer understand the context of the conversation and perform a more effective review.

Another critical aspect of an email threading tool is its ability to highlight missing emails in a particular chain. Including only some emails in a chain could lead to holes in defence or questions concerning a company's preservation process.