I have been new to HR and I hope to get help from here.

As working in an small company with few staff, reposition and task delicate but seem problem occur like

Stress scold by manager (course of mistake or others mistake)
Too many task (but still can approach mobile message every minute)
Other colleagues also the same (but some can complete their task)
Etc

How am I able to judge?

Specifically what is too judge? I assume you are a worker, and probably have seen there less time than others but they are less "efficient" and the boss rides you more? Is that the issue?

Please clarify.

May I know what is 'oss'?judge about operation problem or self problem? I need to help improve operation.each people have own task, but they not capable to finish. (almost compound about a week task)when I ask reason and problem to help solve and improve, only the above issue inform.I have my own task to do, that why I rarely with them. Please do give advice.

Your question is not totally understandable. Could you please clarify it? It really makes no sense as it is.

Company operation having problem, slow and always miss or lost item, and not able to submit all report in time as request. I have to check out the problem and solve it. As I notice some co-worker have problem and talk with them. However, I was less confident and not able to judge who and what wrong.They tell lot of others information to compare and all feel so guilty about suspect their ability, although there is task that they delay and not able to submit (almost a week there).
After discuss, I still can't really understand whether is the co-worker have problem or what?
As my own view, I know they wrong, but I don't know how should express to let them know their mistake and improve. Lot of reason that stop me like others also the same, why only me pointed.

Thank You.

OK, I'm guessing that English is not your native language. If you are HR, you shouldn't need to judge the work of line personnel. That is up to their functional supervisors. You can discuss with the supervisors if they feel workers are not performing up to what is needed.

P.S. the oss was a type it was supposed to be boss.

Yes I meant boss but I have to ask what kind of training for YOUR job have you and your colleagues had as it appears none of you has a clue as to what to do to make your job better. That includes YOUR boss.

I agree, unless you are a HR manager and this is a HR working having the problem, it is not HR that is to solve the issue, but the manager over the department.

But it appears you already have an opinion.

Others get the work done
The person is on message all the time.

It appears they are not working properly and you know it. So why are you having problem reporting what you see

Yes I am so confused when I received the info.. they tell me it not just them only.. but why they have to be treat like that.. fairness is need to all..
As if a operation person in charge, any advise can give as guide lines?

How can we advise you when we can't understand the situation? Your posts are very hard to read.

Sorry to tell you... but "fairness" isn't something one can expect in the world. And everyone's definition of "fairness" isn't the same. A new hire can't expect the same things an employee that's been there 20+ years can expect.

How long have you been working? How long at this employer? How many other employers have you worked at doing a similar type of work.

One has to adapt to what is expected of them at each employer. Everyone doesn't adapt to you. If you don't or can't... there will certainly be problems.

You are there, we are here but you have not identified your operational problems. As a manager its up to you to determine how best to address the issue of people not being able to complete their tasks on time, and efficiently. Are they poorly trained or don't have the skills or management hasn't given them the proper support. What do YOU think the problem is? If you don't know what to do about it, the workers surely don't.