Hello Sana,
While P. Xavier Raj, B.Saikumar & other members have given very valid & realistic suggestions, there's also a lot of truth in what Ben Simonton mentioned.
You mentioned THREE areas of concern: (1) do not give sufficicient notice (2) they leave early (3) sometime due to absconding.
Pl note that the causes/reasons of each of them COULD & most likely WOULD be different. So clubbing all the 3 could lead you to erroneous conclusions.
Like Ben Simonton mentioned, a lot depends on the organizational culture--which in-turn depends on the people @ the Top, ie. the Management/Managers.
Coming to one of the causes you mentioned: ABSCONDING.
Why would anyone take the trouble of 'absconding'? At the entry level, maybe he/she wouldn't be aware about the consequences of such an act, but after gaining some experience, the importance of Experience/Relieving Letters would be known to them. But, yet, if such employees 'abscond', there's obviously some fear about a possible unfair treatment by the company if they reveal their plan to quit. This leads to the Management Model in your company--non-transparency in employee relations, unethical/unfair practices, unfair salary/promotion hikes or the lack of a clear policy in such issues, etc, etc.
Pl note that I am NOT saying that all of these exist in your company--I am just pointing to the various POSSIBILITIES. It's YOU who needs to figure-out if any of them exist & how best to handle each core value/issue.
However, there will always be exceptions among employees [incorrigible guys, so to say]--if you do an exercise on how many of those who quit actually fall into this 'absconding' category, it will enable you to target the corrective mechanism properly & effectively.
Coming to the other 2 causes you mentioned: INSUFFICIENT NOTICE/LEAVING EARLY [both are by & large the same, unless you had different context/situation in-mind].
This category of employees DO resign & give some response-time for you/HR. I think this is where Exit Interviews suggested by the members will surely help you.
But, frankly, a word of caution here. The result will depend on HOW THE EMPLOYEE VIEWS the Exit interview process. This again, at the sub-conscious level gets decided by the type of experiences he/she has had while working--if it has been one of suspicion [in attitudes or work or general behavioural pattern by the superiors], the chances of Exit Interviews being more a formality than of any REAL use are HIGH. He/she will give you the answers YOU WANT to hear--NOT what he/she ACTUALLY feels inside.
I have seen BOTH types of situations--employees coming out with the ACTUAL reasons for quitting as well as giving some crap just for the HR to file his/her Report after the exercise.
Hope you get the point.
Another point/solution mentioned by the members was of having formal HR/Training policies. More than having HR Policies, it's MORE IMPORTANT to focus on their proper, even-handed & fair Implementation.
Going by what you also mentioned ['.......really get shocked hearing such answers form managers /general managers'], I think your problem is NOT the employees per se, but the Managers--especially if your 'absconding' figures are high.
All the Best.
Rgds,
TS