See the following link to learn more.

ttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC3354504/

Thanks

Nice question

I will follow the subject to learn more

Greetings

Tough metric , there are organizations that do it

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3354504/

It is pretty difficult for  Medicine and Biology based journals .

 Indexation of a journal is considered a reflection of its quality.Journal indexed with ISI are based on following Selection Criteria:  Quality of Publication,,,Manuscript Quality,,,

Presentational Quality,,,Editorial Quality

See the following link to learn more.

ttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC3354504/

Thanks

Agree with Dr Munaf and Dr Aparna Sathya

Dear , Mourad . Thank you for sharing.

In my opinion the journals which classified within scopus index are based on to be indexed.

With my best wishes.

Dr.Y.A.Salih

Hi to everyone

Once a journal is indexed by a database, it is immediately made available to all users of that database. Some databases index titles, some index full articles while some others index only the abstract and/or references. There are several abstracting and indexing services available today. Some are affiliated with institutions (e.g., PubMed maintained by the United States National Library of Medicine at the National Institute of Health) while some are provided by publishers (e.g., Scopus by Elsevier).

I think the following points should be considered in this endevour:

1. Choose the right database

Choose a database that indexes journals from your field. It is also important to understand the features the database provides.

2. Understand the selection process followed by the database you have chosen

Some general criteria that databases use to evaluate a journal’s suitability for indexing are quality of content published, publishing timeliness, and journal workflow and processes.

3. Ensure your journal processes are smooth and efficient

Make sure your journal meets the basic publication standards required by the industry (author friendly systems, smooth and timely peer reviews, easy accessibility, etc.).

4. Approach a company with multiple databases

Companies like Elsevier and Thomson Reuters offer several indexes that cater to journals. In such cases, it might be a good idea to check the full list of products or services offered and apply to those that are relevant to your journal.

Regards,

Ata

The answers were too useful. They enrich my humble knowledge about this.

Quality of research papers and regularity of the journal are the bases for indexing on the data bases like Scopus, Web of Sciences, Google Scholar, etc.

"Indexation of a journal is considered a reflection of its quality. Indexed journals are considered to be of higher scientific quality as compared to non-indexed journals. Indexation of medical journals has become a debatable issue. For a long-time Index Medicus has been the most comprehensive index of medical scientific journal articles. It is being publication since 1879. Over the years, many other popular indexation services have developed. These include MedLine, PubMed, EMBASE, SCOPUS, EBSCO Publishing's Electronic Databases, SCIRUS among others. There are various regional and national versions of Index Medicus such as African Index Medicus."

I recommended Dr. Munaf answer.

Thank you  Dear Dr. Raid Al-Ani for your kind recommendation.

With my best wishes to success.

Good luck

Dr. Y.A.Salih

I think , periodicity of journal, citation of published papers in other high impact factor journals, referral of journal by world known indexing agencies , how old is the journal , they  all come in picture..

I think it is the quality of the journal (ELSEVIR, JSTOR), the subject of its specialty (PsychLit for psychology, ERIC for education, EBSCO and ProQuest for business and other social sciences, MEDLINE and PibMed for medical,),referals, the age of the journal, its popularity and amount of citations by scholars and how it is recognised in academia.

Dr Réagan

Indexing a kind of grading of the journal in its specific field based on the quality of research articles published and its reference in other articles/ readership and also certain standards like the reviewing standards/ the editorial board etc.

To me it depends on what ones institution accepts but I will prefer SCOPUS

Indexing is based on the quality of papers published. It may depend on various other factors as discussed in earlier responses.  In science, SCI(Science Citation Indexing)  by Thomson Reuters is at the top. SCOPUS indexing is good, but not as good as SCI. To me, Google Scholar indexing has no importance.

It is based on the quality of papers published and the number of citations.