Time = Money
The diploma course requires more classes covering a wider range of topics than the typical certificate course. A student who has a career diploma can command a higher salary upon graduation than one who only has a certificate.
Knowledge
When you graduate from a career diploma program, you are more likely to feel confident that you are ready to start a job in your field. You will likely face less of a learning curve on the job as you have been exposed to more training and theory about your chosen career than a person with only a certificate. Diplomas provide more in-depth knowledge of a field of study and are of longer duration than certificates and certificates are specialization in a particular skill set.
Graduate diplomas are an increasingly popular option amongst post-undergraduate professionals.
Some schools use ‘certificate’ to describe programs that focus on very specialized knowledge, while diploma programs are considered more comprehensive of an entire subject area (i.e. computer programming).
Job Prospects
The more education you have, the better chances you have of finding a job. If several candidates apply for the same position, having a degree instead of a certificate can help your resume land at the top of the pile.
Read more: http://www.ehow.com/info_7798230_career-diploma-vs-certificate.html