Ryan Shorthouse is the CEO of Bright Blue

There has been much political focus on the learning loss experienced by schoolchildren during the Covid-19 pandemic.

The evidence on the scale of the learning loss is strong, with younger and poorer children more badly affected, particularly in maths. The evidence on remedial interventions is also relatively robust, with Education Endowment Foundation research highlighting the efficacy of one-to-one or small group tutoring, which the government has duly invested billions in.

It’s still not enough, hence the resignation of Sir Kevan Collins as the education recovery commissioner over the Chancellor’s refusal to fund extended school hours. But the point still stands: all attention and resources of the Department for Education after lockdown life has been on supporting schools.

Time to turn to the early years, where the evidence on the impact of the pandemic is – yes, much more embryonic, but probably much graver.

Sadly, the main means to assess development – through the Early Years Foundation Stage, when children are aged two and five – were interrupted in 2020 and 2021. But the evidence base that is building, albeit patchy, is worrying.

The Healthy Child Programme, led by health visiting teams, reveals a marked decline between 2019 and 2021 in the proportion of two year olds achieving the expected level of the five main areas of cognitive and social development measured, such as communication, motor, and problem-solving skills.

Though there is a paucity of UK evidence, the Early Intervention Foundation has found international studies that show many aspects of the physical development of infants have also been detrimentally affected by Covid-19, with rates of obesity, physical inactivity, and poor sleep on the rise, with those from the lowest-income backgrounds experiencing the most adverse outcomes.

Development in infancy can be influenced by a number of environmental factors – the home environment, primarily – but also participation in high-quality formal childcare, where it has been demonstrated that it generates longstanding gains to attainment, for those from deprived backgrounds in particular.

So the drop in pre-school attendance, with almost complete absence in the first lockdown of 2020 and still not recovered to pre-pandemic levels even now, must be driving to a large extent these developmental deficits.

We should not be deterministic about early years development. It is not the only window in which to transform the developmental trajectory of a person, but it is the most important.

The work of Dr Leon Feinstein has shown that relative test scores of five year olds strongly predicts relative A-level performance. Professor James Heckman explains that because skill formation is complementary, strong developmental foundations in infancy is therefore paramount. That is why we should be worried most about the impact of the pandemic on early years development – it will have more profound and long-lasting consequences.

Despite this, there is nowhere near the same level of evidence on the impact of the pandemic on – and effectiveness of remedial interventions for – learning loss among pre-school children relative to schoolchildren. The generation and promotion of such evidence needs to happen as soon as possible.

And government will need to lead the way in ensuring the necessary programmes and policies are put in place to bolster early years development. If not, the poorest children will just fall further behind, since the attainment gap starts with school readiness and only widens thereafter.

Extended school hours, commonly championed to help schoolchildren catch-up after Covid, has reasonably good evidence to support it. There is much more ambiguity around this with pre-school education. Being in formal childcare any longer than 15 hours a week, according to research from Professor Kathy Sylva, does not appear to offer additional cognitive developmental gains.

However, many under-fives – especially those form low-income backgrounds – are not even in formal childcare for this long, despite the free entitlement to 15 hours for the most deprived 2-year-olds, and at least 15 hours for all 3- and 4-year-olds. How do we make sure they do?

We need some carrot, maybe some stick. To entice parents, ensure they see pre-school education as unmissable, the quality of provision needs to be noticeably improved. Any additional state should now be spent on the quality rather than quantity of formal childcare. Higher staff qualifications seem to be the most important determinant of quality, above – for example – unnecessarily strict and expensive staff-to-child ratios in the UK. We need significant salary supplements to attract and retain the best educators into early years settings in the most deprived areas.

But maybe it’s time to make pre-school education – specifically, the free entitlement for some two year olds and all three and four years – compulsory? After all, the evidence tells us that pre-school is the most important part of the education system. This makes the current education starting age rather arbitrary.