Generally, SCI and SCIE journals are considered to have a similar level of quality. However, in some countries, like for example in Korea (I think in China and Japan as well), SCI journals are given more weight (or perceived to have higher quality) than SCIE journals. Perhaps, it is also because a lot of SCI journals have longer history than SCIE journals. As what I have noticed, many of the top-ranked journals in their respective fields are SCI journals, and only a few SCIE journals. And many of the Society-sponsored journals are SCIE. So the 'perception' of quality is relative to where you are located.
SCIE journals are the expanded and extended list of SCI journals. In future some more good journals will be included in SCIE based on the quality. SCI or SCIE journals and the published papers are of same quality as for as its quality and recognition are concerned. In civil engineering field many journals listed in SCIE are of very high quality and publishing papers is these journals is very difficult. Once published, you have really achieved something impossible. Publish few papers in SCI or SCIE to have international recognition.
To Answer Prakash Kumar Singh: There is nothing like paid SCI journals. Once you pay and publish, you have compromised the quality. Any paper can be published if one is ready to pay. Avoid pay and publish concept to have more credibility of your paper. I have seen few good papers in paid journals as well. Some times you may have to publish in other journals, if your paper is not of high quality. Good wishes.
SCI is not covering many journals of engineering discipline. Now a days good civil engineering journals are listed in SCIE. I agree with Mr. Hui Yai that SCI is better if journals cover your area. Good wishes.
In my field of study, coastal science and engineering, there are only about 40% good journals in SCI and the other 60% in SCIE. So the difference between SCI and SCIE is not in quality. As the letter from Thomson Reuters, the difference lies in storage media.
All the Journals listed in SCI are in SCIE, however the reverse is not the same. This is irrespective of the quality of journals. Yes I agree that older journals are in SCI and newer ones are in SCIE due to space constrain.
The Science Citation Index (SCI) is a sub-set of the Science Citation Index Expanded (SCIE), containing journals that rank competitively among the most highly-cited core journals in their category or categories. The Science Citation Index Expanded is essentially the web version of what used to be a database available only on CDRom/Diskette. When selecting the journals for the Science Citation Index we choose the top journals from each subject category and supplement this with top regional journals from each category to give broad geographic and multidisciplinary coverage. The evaluation of and acceptance of a journal for the Science Citation Index Expanded or the Science Citation Index is essentially the same with one major difference. While every science journal in our database is covered in the Science Citation Index Expanded and only those journals of relatively significantly higher citation impact are selected for the Science Citation Index. In other words, Science Citation Index covers only the most highly cited, highest impact journals in each category. This is because of the constraints of the CDROM and print media there is no difference in the selection process for Science Citation Index and Science Citation Index Expanded journals.
There is no difference and SCI is removed from Web of Science Mater Journals list. For more information on this visit "https://support.clarivate.com/ScientificandAcademicResearch/s/article/Master-Journal-List-Removal-of-SCI?language=en_US" which is official site of web of science.
"Following updated editorial guidelines and criteria, Science Citation Index Expanded (SCIE) is our most comprehensive and selective flagship collection covering the sciences. As there is no longer any difference between the editorial selection criteria for SCIE and SCI, we are removing SCI to reduce overlap and unnecessary complexity in our collections."
Web of Science: Science Citation Index Expanded (SCIE)
"Created as SCI in 1964, Science Citation Index Expanded™ now indexes over 9,200 of the world’s most impactful journals across 178 scientific disciplines. More than 53 million records and 1.18 billion cited references date back from 1900 to present."
SCI was the original citations index for science disciplines, followed by SSCI for the social sciences, but SCI has now been overtaken by its expanded counterpart, namely SCIE.
Recently, Clarivate Analytics Announces the Integration of SCI and SCIE to SCIE from 2020. The journal indexing such as Science Citation Index (SCI) and Science Citation Index Expanded (SCIE) are received more good reputation across the publishing industries to measure performance and citation metrics of both at the journal and author level.
The journals indexed under this databases are considered to be the world’s leading journals of science and technology, because of a rigorous selection process. The different indexing categories carried out by the journal evaluation companies create more confusion among researchers to choose the right journal for the publication of their scientific manuscripts.
SCI and SCIE do not differ in the quality of the paper, but only in the difference that SCI is data provided on CD/DVD and SCIE is data provided online. Also, it creates confusion among SCI and SCIE’s classification and identification of the journals. To solve this problem, Clarivate Analytics said it has been working to set internal policies and add information and URLs for each journal since October 2019, and that it will provide SCI by integrating SCI into SCIE without officially using SCI classification as of January 3, 2020.
With this information, all SCI journals in the Web of Science Core Collection are classified as SCIE form January 2020.
If SCI is merged into SCIE, Why Journals are mentioned both SCI and SCIE in their abstracting and indexing? They would have shown only SCIE (It means it is included SCI) leads no confusion. Currently all SCI journals are indexed in SCIE, But all SCIE journals not indexed in SCI. It indicates that both are different.