A method is disclosed for determining the translational efficiency of an individual codon in a cell. The method includes introducing into the cell a synthetic construct including a reporter polynucleotide fused in frame with a tandem repeat of the individual codon, wherein the reporter polynucleotide encodes a reporter protein, and wherein the synthetic construct is operably linked to a regulatory polynucleotide; and measuring expression of the reporter protein in the cell to determine the translational efficiency of the codon.