My personal opinion is that the board exams need to go. As much as people would root for equality and the like, I have seen over a span of ~5 years that the board exams do have problems.
There are an enormous number of students writing the board exams year after year. The papers are corrected in batches by various teachers, each of which corrects differently, the knowledge level varies from person to person, etc. There is thus no guarantee that every teacher corrects in the exact same manner - thus it can happen that all students are NOT given the same marks for the same answers!
Not to mention that there is quite a bit of pressure on the teachers to submit the corrected papers in a given period of time. With increasing number of papers each year, the assessment quality goes down. Correction in these five years, I observed, has become more and more lenient.
There are other problems too with the board exam, both at the 12th and the 10th level. I have observed students topping school exam after school exam for years, yet in the boards they don't quite fare that well (they fare well enough but nowhere near the top). Granted this does not happen to everybody, but I have seen a fair number of students suffering from this (especially in language subjects, board scores are often lower than scores in every single test throughout the academic year).
It is my opinion that the time pressures of correction and varying levels of competence of correcting teachers negatively affects the scores of some very good students in the country.
A school based correction at the 10th std. level is better because the time pressure reduces for the teachers, and the papers are corrected as per expectations. In the board exam, things like your handwriting and underlining some important points still count.
Even if you account for the partiality factor, I have never seen partiality or troubles with the teachers account for more than 5 marks in any subject. However, I have seen far worse deltas with the expected performance of the student over the years with the actual board exam scores.
You have to consider that every school and college wants good results. The more number of students passing and scoring good marks, the better the reputation. For this reason there can be NO partiality at the 10th/12th standard level in correction even at the school level since these scores will be used for going to higher studies.
With school based correction, the teachers know their students and get more time to properly analyze the papers - hence resulting in a better correction.
I am not saying school based correction is the CURE - it is not, because the CURE means better salaries for teachers and MUCH more qualified teachers (for some localities), but a shift to such a system will *always* be beneficial for students.
Addendum: I know people will say that if you study you will get marks and all.......Sadly, this is NOT true. The board exam is open to moderation - the papers that score the highest marks go for moderation, checked by a few other people and then the marks are somehow reduced by finding some idiotic reasons like "answer that does not conform with the model answer", "different explanation, cut half mark" etc.
This is why a lot of students scoring highest marks in any subject throughout their years in the college examinations are unable to repeat the success in the board examination. Until we have a better standard for correction and teachers in place, the board exams need to go.
I speak from my personal experience - I was never very good at any other subjects till my 10th; however I always stood first or second since KG all the way to the final college test of my 10th in the English and Social subjects. But when the board examination results came - I was nowhere near the top in both subjects (my score was still good though at 88 )! It was not a question of my ability since I stood first again in English in my 11th (college exam), but again the board exam in 12th showed otherwise. It was similar in Biology, after scoring 90+ marks in every college examination in my 12th, scoring in the 80s in the HSC board exam was the least of what I had expected, but things like that happen......
It happens to a lot of students, not just me........Things need to change and fast!