The phrase "are often so low" is correct and usable in written English.
It can be used to describe a situation or condition where something is frequently at a low level or degree.
Example: "The temperatures in winter are often so low that it becomes difficult to go outside without proper clothing."
Alternatives: "are frequently quite low" or "tend to be very low".
Teachers' salaries are often so low that they are forced to live hand-to-mouth, supplementing their work with other jobs or spending decades disputing their pay (as is the case in Kenya).
This is the internet age, when barriers to entry into markets are often so low that customers have any number of brands from which to choose.
First, asymptomatic parasitemias are often so low that they often escape detection by microscopy, the widely used tool for malaria diagnosis [ 5].
One unique feature of miRNA data is that the expression level of miRNAs in different tissues or treatment conditions are often so low that they are below instruments' DL, resulting in a large portion of left-censored measurements.
Their income levels are often so low that they can afford to purchase only the cheapest and most basic foods, and since they cannot afford to rent housing they are forced to camp in makeshift shanty towns on the periphery of cities.
He has better luck on his next argument, which is that the two-line pass rule hampered offence and generally was one of the reasons scores in the days before the lockout were often so low.
It was introduced by an American charity called Conservation International, which realised the going rate for logging concessions was often so low that it could afford to outbid the foresters.
The amount of time allocated to GTAs for marking is often so low (one hour per student, per course at my institution) that we regularly exceed it because we want to give high quality, thorough feedback.
Even when insurance does pay, the reimbursement rate is often so low that many doctors say it does not come close to covering the time and expertise needed to perform and interpret the exams.
The analysis showed that BPA levels were often so low that it was below the ability of current toxicological methods to detect it, raising the possibility that most instances of high BPA dose might have been the result of contamination from tubes and plastics in hospitals.
Furthermore, the graphene concentration in these solvents is often so low (<0.1 mg mL−1) that several tens of print passes are required to obtain functional devices, which can reduce efficiency of the technique.
