I'm not seeing any research linked. It will have to be pretty convincingly done too because we've seen a metric ship load of issues in psych research of late.
I don't have an opinion on the issue at hand. "Because the science says" With nothing in support makes me really suspicious. It really starts looking like "Because $authority says so you may not question" Which is the opposite of what scientific inquiry is meant to be.
They are not the only one, I see the same. Kids without math drills have problems in storing crucial bits of information in long-term memory and consequently fare worse at solving simple arithmetic problems than myself when I was much younger. I'm not talking about complex things but basic arithmetic, like multiplying digits, adding fractions or, more importantly, dealing with ratios. Drills give you a considerable advantage here.
I have another peice of anecdata with my parents/grandparents. They grew up in the USSR and went through school there, drilling (according to them) was extremely common.
They can still remember some peoms verbatim over 70 years later (in my grandfathers case). And they still remember/understand pretty much all the math they were taught. When I was doing my Advanced Highers (final exams in Scotland) I was asking my parents for help and they could answer all the questions without looking things up.
I looked up the exam paper[0] I sat, I'm pretty sure there's no way I'd get an A again if I sat it right now without studying for it. But I'm pretty sure my parents still woudl.
I had a bit of schooling in that kind of educational system (Asia) before continuing schooling in North America. I'd say that you there is no free lunch. You're always giving up something for something else.
I had a job 10 years ago doing in-person training at a company trying to digitize their paper-based office for the first time. They were in a commodity distribution business, so while the math isn't hard, there is a lot of day-to-day arithmetic (conversion between unit of measure and price/unit vs total price) for all the employees from the warehouse guy to the sales staff.
The system introduced a change in their workflow. Before in their old manual paper system, people just kind of put things on a truck and figure out later how much got shipped and how much to invoice a customer. The whole can be very hand-wavy. There was no live inventory system either.
Digitization meant that sales have to write sales orders that had precise units to be sold. Based on inventory, they know how much they will actually ship and they know that down to the dollar. Everybody suddenly had to start being aware of the math involved in their work.
It was kind of funny to see a bunch of blue-collar, ex-con, high school dropouts learning faster than all the college-education office workers. The college-educated guys were too drill-orientated and approached the work like the math worksheets that everybody is talking about. The ex-cons had a working relationship with the numbers on the screen and the things that are hanging off their forklifts. Many of the white-collar clerks had been getting by memorizing formulas. They had no idea what any of those formulas mean.
Sure, you can drill them. I am just saying you should intermix them with other problems.
I am not telling you to do multiplying digit only 1 times. That would be silly. I would be telling you should mix up multiplying digits with other previously learned concepts, say 10 addition and 10 subtraction questions, and the rest can be 80 multiplying digit problems. I don't know the optimal intermixing ratio here, but it shouldn't be a straight 100 multiplying digit problems which all use the same algorithm to solve it.
Drilling and repetition is good, but there's the danger of having illusory mastery because it's already there in short term memory. Your goal is to encode those skills into long term memory.
