The Commons home affairs committee heard almost three hours of evidence about the Windrush crisis from the home secretary, Amber Rudd, one of her senior officials and a series of immigration experts. But a number of questions remain:

1. What compensation will those wrongly targeted receive?

Asked about this at prime minister’s questions, Theresa May said Rudd would “set out the details of that compensation scheme in due course”. Quizzed at the committee, the home secretary had nothing more to add. Yes, she assured the MPs, those who had wrongly lost jobs, homes or benefits would get recompense. But it remains to be seen when, how much, and how they apply.

2. How many people are potentially affected by the Windrush crisis?

A lot. In the short space since the Windrush hotline was set up, Glynn Williams, the head of immigration for the Home Office, told the committee it had taken 3,800 calls, of which 1,364 had been identified as being Windrush cases. This seems set to rise.

So far, he said, 91 appointments had been made, 25 had taken place and 23 documents issued. Earlier in the day, a junior minister, Nadhim Zahawi, had pledged all cases would be sorted out within a fortnight. This looks a tough ask.

3. Are there targets set for deportations?

It depends who you ask. Giving evidence before Rudd, the general secretary of the ISU immigration workers’ union, Lucy Moreton, said there was a target for net removals, and that it was broken down by region. But asked about this, Williams said it was not the case.

As the hearing continued, Moreton told Sky News she was “somewhat bemused” at this answer, and said the target was 8,337, with targets on posters in regional centres.

Asked about Moreton’s later comments, Williams insisted he was right: “I said earlier on, I don’t think they do exist. There are no published removals targets and there is nothing broken down by region.” A slightly puzzled Rudd promised to look into it.

4. Who is to blame?

Rudd was somewhat evasive on this, at times seeming to accept there was a wider issue connected to the so-called hostile environment approach, but then rejecting the idea that this had “blurred the lines” between targeting “illicit migrants” and those with the right to be in the UK.

At times she seemed to blame Home Office officials, saying her department needed “to have a more personal approach in terms of engaging with people”.

But she also targeted previous governments for not realising the undocumented status of many in the Windrush generation could cause problems, saying it was “disappointing no previous governments saw this coming”.

5. How many people have been wrongly detained or deported?

We still don’t know. On removals, Rudd said: “The answer is, not as far as we can see at the moment.” But, she added, this was not definitive as checks were still being made.

Asked by the committee chair, Labour’s Yvette Cooper, how many people had been wrongly detained, Rudd said – to Cooper’s apparent surprise – that no work had yet been done on this, adding: “I have to be frank, I am prioritising the removal for now.”