Not only has he been profoundly ineffectual, he's actually neglected to ask questions in three of the six instances.
He's a bit special, is Jez.
From The Guardian:
PMQs - Snap verdict: The good news for Corbyn is that PMQs, while entertaining theatre, which has a lot of influence on the standing of leaders with their MPs, and some impact on the way parties and leaders are perceived by the public, it is not ultimately decisive. Just ask William Hague. This ought to be a consolation because, on a day when May has just had to execute the biggest U-turn of her prime ministerial career, at considerable cost to the government’s reputation for economic competence, Corbyn failed dismally to exploit this at the despatch box. He had clearly prepared a set of questions about education and was not quick-witted enough to abandon them and instead devote all six questions to the NICs U-turn, as he should have done. A better leader would have taunted her with a series of questions about why she defended the policy last week. Or at least produce an effective soundbite, as Angus Robertson did. Instead, even when Corbyn was commenting on NICs, he got diverted into the abuse of self-employment by employers - an important topic, but one where May has a case, because of the Taylor review.
I actually flattered him. He in fact only actually asked two questions of the six he's allowed.
Question 1: “Big business evades a lot of national insurance through bogus self employment.” No question.
Question 2: “What is she going to do to fill that Budget black hole?” Question.
Question 3: “It is a grossly unfair system where those in self employment pay some national insurance, employers do not and benefit from it. That is a gross injustice which has to be addressed.” No question.
Question 4: “Cuts to social care and cuts to people with disabilities. That is the agenda of her government and everybody knows it.” No question.
Question 5: “Can she say what she’s doing to help the worst off and poorest in our society rather than continuing cutting local government expenditure, schools expenditure and underfunding social care.” Question, about schools.
Question 6: “What she has to do is address the issues of injustice and inequality in our society, and a government that’s dedicated to widening the gap, not helping those that are hard up, working self-employed to try and make ends meet, and not getting access to any benefits at the same time.” No question.