The phrase "a useful approximation for" is correct and usable in written English.
It can be used when discussing a method or calculation that provides a close estimate of a value or concept.
Example: "In many cases, the formula serves as a useful approximation for predicting future trends in the market."
Alternatives: "a helpful estimate for" or "a practical approximation of".
The method appears to be a useful approximation for a wide variety of problems.
The main focus is on thin shell theory, which provides a useful approximation for many deformation scenarios.
In materials science, this is a useful approximation for semi-conductors and a very good approximation for metals at room temperature.
These assumptions are not too restrictive and the solution appears to be a useful approximation for a broad range of material-mill combinations.
The initial rate of development of constitutional undercooling is shown to be equivalent to the growth restriction factor and is a useful approximation for the effect of solute on grain size when potent nucleant substrates are present.
These models rendered a useful approximation for binding requirements in the BBB-choline transporter and, until such time as the cloned transporter becomes available, may have significant utility in developing a predictive model for the rational design of drugs targeted to the brain.
Although the results should be interpreted cautiously, they serve as a useful approximation of the sufficient sample size appropriate for modularity analysis.
The body mass index is a useful approximation of body fat, but it can be misleading for muscular athletic individuals, like President Bush, who would be considered overweight, as the article notes.
A useful approximation of Eqs.
Thus the MC characterizes a point at which we have constructed a useful approximation of the complete system.
Economists have extrapolated a useful approximation of uncovered interest rate parity that follows intuitively from these assumptions.
