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Academic journal articles are only as impactful as they are discoverable, and online discovery hinges almost entirely on one thing — indexing. Without proper indexing by discovery services, researchers will be hard-pressed to find even the most groundbreaking scholarly articles.

From general search engines to discipline-specific databases and aggregators, there are numerous indexing options that journals can pursue, all with different benefits. Each index a journal seeks inclusion in will have its own requirements for entry and likely take time to get set up, so it’s important to pick a few to start, then follow through with the necessary steps to be added to those indexes before moving on to new ones.

What types of indexes should publishers seek to add their journals to first? How should publishers go about prioritizing indexing initiatives? What steps should publishers take to keep improving their journal indexing outcomes? In this blog post, we break down answers to these common indexing questions, covering everything you need to know to initiate and keep building upon a successful journal indexing strategy. Read on to learn:

  1. Key index types to consider
  2. How to develop an indexing strategy for one or more titles
  3. Tips for optimizing your article indexing outcomes

This guide starts with indexing basics and then moves on to more advanced tips. Feel free to use the section links above to skip ahead based on where you are in your journal indexing journey. Let’s get started!

Key index types to consider

Before embarking on any journal indexing initiative, it’s important to first consider the different index types available and start developing a shortlist of indexes you’d like your journal or journals to be added to. The more quality indexes on your list, the better! Each index your journals are added to will help expand their reach and potential impacts. From there, you can start mapping out an indexing strategy based on your discovery goals and the criteria of the different indexes you’re interested in. Keep in mind that getting added to popular disciplinary databases, such as MEDLINE for journals in the biomedical and life sciences, will likely take time because many have strict publication requirements journals must meet before being eligible for inclusion (more on this later).

All publishers should strive to have their journals added to both scholarly databases and free general search engines to make their articles as discoverable as possible. Many scholars are starting their research via free online search engines that they can access anywhere, such as Google Scholar, so you’ll want to ensure your articles are visible in those search results. For open access (OA) journals, in particular, ensuring content is easy to find via free online search engines and indexes is paramount to maximizing article accessibility.

Keep in mind that different indexes will offer different levels of added discovery potential. Some databases index just article titles, abstracts, and/or references, whereas some index full article files. Generally, indexes that ingest more article information and/or full text will provide greater discovery potential.

Below we outline common index types and the benefits of each for journals.

1. General search engines

We’re starting off with search engine indexing since, as noted, scholars are increasingly using general and scholarly internet search engines to conduct research. Many authors also want to know that their articles will appear in search engines that are easily accessible to practitioners in their field as well as the general public — not hidden away in academic databases only. Regardless of which academic indexes you choose to focus on for your journals, you must, must, must make search engine indexing a priority. We can’t stress this enough.

Another benefit of search-engine indexing is that any journal can be added to a search engine index regardless of its publication history, citation count, or other time-bound specifications academic databases may require. Since journals can be added to search engines right away, they are great indexing starting points.

There are two layers of search engine indexing to consider to make your journals more discoverable:

  1. Being indexed by general search engines like Google and Bing
  2. Being included in mainstream scholarly search engines, the big two being Google Scholar and Microsoft Academic

We’ll tackle general search engines first and then move on to mainstream scholarly search engines.

Starting with general search engines — the good news is these indexes will be “looking” for your content. Search engines, like Google and Bing, scour the web for content to index via computer programs commonly referred to as “crawlers,” “spiders,” or “bots.” As long as you don’t have “no-index” tags on any of your journal website pages (at least the ones you want crawlers to parse!), your content will be eligible to be crawled by search engines. You can do a quick check to make sure your journal websites are showing up in search results by typing “site:” followed by the URL you want to check (no spaces in between) in the search bar. If your site shows up, it’s being indexed.

Once you know that your journal websites can be crawled by general search engines, you’ll want to follow search engine optimization (SEO) best practices to improve the chances of your journal homepages and articles showing up at the top of search results. Some tips to start include:

  • Host all journal articles on their own webpages (this makes it easier for crawlers to find them)
  • Ensure your journal websites have logical navigation for human visitors and search engine crawlers
  • Create sitemaps for your journal websites and submit them to general search engines like Google
  • Maintain your sitemaps over time, so all pages are included
  • Ensure you have robust, quality content on all of your journal’s main web pages - use longtailed keywords for better search results
  • Make sure all of your pages (main webpages and article pages) have HTML metatags that provide descriptive metadata to search engines

2. Scholarly search engines

As you’re working on your journal website SEO, you’ll also want to start taking necessary steps to have your journal articles added to mainstream scholarly search engines — the top ones to shoot for are Google Scholar and Microsoft Academic. Getting added to these search engines will require the best practices outlined above, as well as adherence to some additional inclusion criteria.

A common misconception about Google Scholar and Microsoft Academic is that they index all of the content they have access to regardless of the content type or quality. This is not the case. Both scholarly search engines have certain quality controls in place and do take steps to ensure the websites they index are academic sources. You can find the information you need for Google Scholar indexing here and Microsoft Academic indexing here. We’ve also compiled a complete guide to Google Scholar indexing.

At this point, you may be thinking that all sounds like a lot of website set up and maintenance work — and it can be, especially when you’re just starting out. Despite the seeming omnipotence of online search engines, they do need a fair bit of help to be able to find and crawl website pages. If you’re using a journal hosting platform, many of the SEO best practices outlined here, as well as scholarly search engine requirements, may already be taken care of for you — be sure to ask your provider about this if you’re not sure! For example, all journals using Scholastica’s OA publishing platform have search optimized websites and automatic Google Scholar indexing. Publishers with custom websites managed by external or in-house development teams will have to take a more proactive role in ensuring their journal websites follow SEO best practices.

3. General and discipline-specific scholarly indexing databases

In addition to getting indexed in general and scholarly search engines, you’ll also want to seek inclusion in scholarly indexing databases. You can have your journals added to general indexing databases that cover all or multiple disciplines and/or discipline-specific databases.

Some of the most popular general scholarly databases to consider include:

  • Ulrichsweb: A general database for periodicals across disciplines.
  • Directory of Open Access Journals (DOAJ): A community-curated online directory of peer-reviewed open access journals (we compiled a complete guide to DOAJ indexing here).
  • Scopus: The largest abstract and citation database of peer-reviewed literature.
  • Web of Science: One of the largest global citation databases (we compiled a complete guide to WoS indexing here).
  • Academic Search (EBSCO): A full-text coverage database of scholarly journal, magazine, and newspaper articles.

The discipline-specific indexes you you choose to apply for will, of course, depend on the disciplinary areas your journals cover. If you’re not sure which indexes are the most widely used in a given journal’s discipline or across certain interdisciplinary areas, start to ask around. Query your authors, editors, reviewers, and readers to find out which discipline-specific databases they use.

There are many discipline-specific databases out there to look into. And some larger databases contain discipline-specific segments, such as the Web of Science Core Collections — this includes the Science Citation Index Expanded, Social Sciences Citation Index, and Arts & Humanities Citation Index. Wikipedia has a long list of academic indexes, both general and discipline-specific, that you can check out here. The University of Miami Library also has a comprehensive index listing here.

As a rule of thumb, if your journal is an OA publication, it’s a good idea to make getting added to the DOAJ a priority. The DOAJ is one of the top general indexing databases in terms of use and reputability that journals can usually apply for relatively early in their publication life. With nearly 12,000 journal members, over 1.2 million visitors every month, and a continually updating stream of journal metadata that’s ingested by all of the major discovery services, the DOAJ is a powerful platform for journal awareness.

How to develop an indexing strategy for one or more titles

Once you know the indexes you want to pursue, it’s time to map out your indexing strategy. Since all indexes will have varying levels of inclusion criteria, it’s a good idea to make a gradual indexing plan. Start with low-hanging fruit indexes that you can have your journals added to early on, and then build up to more selective general and disciplinary-specific scholarly databases such as Scopus and MEDLINE. As you develop your indexing strategy, be sure to account for application review timelines. While some indexes review journals on a rolling basis, others only review applications at certain times throughout the year.

Know the common indexing requirements and where you stand

In good news, many indexing requirements will essentially be standard across databases. Some of the most common index criteria include that all journals should have:

  • International Standard Serial Number (ISSN)
  • Digital Object Identifiers for all articles (DOIs)
  • Editorial board page with names and titles
  • Clearly stated peer review policy
  • Established publishing schedule
  • Established copyright policy
  • At least basic article-level metadata

From there, indexes may have more specific additional guidelines. For example, some indexes require journals, particularly those that publish online-only, to show that their articles are being archived (this is also a general best practice!). Other specific indexing requirements may include:

  • Publication scope: While many indexes accept journals in all disciplines or journals within a broad set of disciplinary areas, such as the humanities and social sciences, some indexes only accept journals that publish within a particular subject area(s).
  • Minimum publication history length: For example, MEDLINE only accepts applications from organizations that have been publishing scholarly content for a minimum of two years.
  • A certain level of publishing professionalization: For example, some indexes look at the readability of published articles and production quality.
  • Geographic diversity: Some indexes look to see that journals have geographically diverse editorial boards and authors.
  • Adequate citations: Some indexes will not accept journals unless they meet a certain citation-level threshold, to demonstrate impact.

Generally speaking, most indexing requirements will be pretty straightforward they just require a high level of attention to detail, which leads us to our next section.

Take your time and be thorough

In all of your indexing endeavors, carving out the time to thoroughly review and fulfill indexing criteria is paramount. Read indexing applications carefully, and then re-read them again — we can’t emphasize this enough. And if you have to update or add information to your journal website to fulfill indexing requirements, be sure to do so in all relevant places and to make required indexing information as specific and explicit as possible. For example, you don’t want to have your DOAJ application sent back because your peer review policy isn’t clearly stated, or because you have missing or inconsistent copyright information on one of your website pages. (Yes, just one page can make or break an application!). If this happens, of course, it’s not the end of the world! All indexes will allow you to reapply. But many indexes require a waiting period for re-application (e.g., DOAJ has a 6-month wait), so it pays to take some extra time to get your application right on the first round.

If you’re not sure whether one of your journals meets the criteria for a particular database, you can visit their website or contact their support staff to find out what you need to do to be eligible. Another great indexing resource is university libraries. Reach out to scholarly communication and/or subject-specific librarians to find out what they recommend. Many libraries are well-versed in helping journals get indexed.

Tips for optimizing your article indexing outcomes

It’s important to keep in mind that a good indexing strategy extends beyond your initial inclusion efforts. The discovery potential of web crawler and article deposit based indexes depends on the level of quality metadata they’re able to parse for all articles. To get the most value out of indexing, adhering to the highest technical standards is key.

Max out your article-level metadata and make regular deposits

To start, focus on maximizing the article-level metadata you make available to indexes. By that, we mean including descriptive HTML meta tags on all article website pages for crawler-based search engine indexes, like Google and Google Scholar, and creating rich machine-readable metadata files for all articles in a standard interoperable language to submit to deposit-based indexes like MEDLINE. The technical indexing standard for academic journals is XML, or extensible markup language, in the JATS format. JATS is preferred or required by many academic indexes, including all National Library of Medicine indexes (i.e., PubMed, PubMed Central, and MEDLINE).

For deposit-based indexes, it’s important not to lose sight of the fact that articles only become discoverable in the index when they are added. So the sooner you’re able to make metadata deposits for new or updated articles in deposit-based indexes, the better. Ideally, you should aim to automate index deposits where possible. Journal publishing platforms can help you here. For example, Scholastica’s OA publishing platform includes the ability to automate deposits to major indexes and discovery services, including DOAJ and Crossref.

Publish articles in digital-first formats

Publishers can improve their journal indexing outcomes further by producing articles in full-text computer formats, including full-text HTML and XML. HTML articles are more search-engine friendly than PDFs because they are machine-readable and can be made mobile-friendly. Mobile-friendliness is now a leading content ranking factor for many search-engine indexes, including Google. Like HTML, XML files are also completely machine-readable. Some leading scholarly indexing databases such as PubMed Central actually require full-text XML article file deposits. Even if not required, depositing full-text XML article files into indexes can be advantageous to journals and scholars as it allows for greater article usage such as text and data mining.

Putting it all together

As you can see from this blog post, journal indexing is a process — and it will take time. It’s well worth the effort to seek inclusion in various relevant indexes, and to work to optimize your indexing outcomes. Getting journals added to relevant indexes will help you expand the reach and reputation of your journal articles, and, consequently, their impacts.

We hope you’ve found this guide useful! You can learn more about how Scholastica is helping OA journal publishers automate indexing steps here and how we’re helping journals produce machine-readable metadata to make articles more discoverable here.

Update note: This blog post was originally published on the 21st of June 2017, and updated on the 29th of April 2020