Thank you dear Christopher J Graham,

This information is really important for me.

Yes, there can be problems. Co-authors could share your data without your permission, so make sure it is copyrighted to you. Also, they can demand changes simply because they are disagreeable people, so don't allow that! In other words, only co-author with nice people, which is more important than their status imo :)

Hi Rahul,

I don't think it's detrimental as long as everyone contributes something to the project and works well with each other. As an example, here's a text that I co-authored with several colleagues:

https://books.google.com/books?id=DiJ5jkY4tbcC&printsec=frontcover&dq=mcelreath+doss+law+enforcement&hl=en&sa=X&ved=0ahUKEwj9rMjgxf_cAhWF61MKHYfkCs8QuwUILjAA#v=onepage&q=mcelreath%20doss%20law%20enforcement&f=false

Have a great day!

--Adrian

There is no problem at all.

There is no problem, if the all authors have contributed with the paper. You need identify what is a really contribution and what is an acknowledgment.

Some institutions, such as ours, do not tend to accept the paper for the promotion of more than three authors.

Thanks to every one who have given the valuable guidance.

Agree in full with Dr Christopher J Graham. Legally and ethically there are no limits! Just authors are the only to decide how many of them are contributors. Furthermore, even cleaning lady in your office or lab has a right to be included into the co-authors list as a participant of your study. Don't smile, it's truth. As far as I remember, the highest count was about 27,000 co-authors on over 100 pages. Just check any Guidelines or Recommendations in Medicine. Or multi-centre study.

However, many institutions establish there own limits of not more than 3-4 authors per paper, mainly to increase the number of publications.

There is no problem at all, if the all authors have contributed in the research work.

Generally NO problem. If your institute have a special rolls then depends your institute rolls.... mean some universities focus first three authors only like Iraq universities ....

There are no technical problems related to the completion of the research ... but there are administrative problems related to the university itself .... From their point of view that the assessment is only for the first three researchers .... I think the university is making a big mistake in this opinion