The date of the transition from the archaeological period known as Iron Age I to Iron Age IIa is a particularly hotly disputed topic, especially because the date of the transition is crucial for elucidating the history and material culture of the reigns of David and Solomon.

According to the so-called high chronology, the transition occurred around 1000 or 980 B.C.E. It is generally recognized that David conquered Jerusalem in about 1000 B.C.E. According to the low chronology, the transition to Iron Age IIa occurred around 920–900 B.C.E. Other opinions place the transition somewhere between the two—in about 950 B.C.

The date is important because the date you choose will determine whether David and Solomon reigned in the archaeologically poor and archaeologically poorly documented Iron I or in the comparatively rich and richly documented Iron IIa.

However, the differences in data between the various schools are not dramatically far apart. They range between 30 and 80 years.

In an attempt to solve this chronological problem and to achieve a more accurate date for the transition period, many scholars have resorted to carbon-14 (or radiocarbon) analysis, which can be performed on any organic substance, like wood or grain. Radio-carbon dating is regarded by many scholars as accurate, precise and scientific, in contrast to the old cultural-historical methods of dating archaeological strata, which the devotees of radiocarbon regard as inaccurate and intuitive. The hope of many scholars who feel that this science-based radiocarbon research will bring the debate to its longed-for solution is, in my view, difficult to adopt.

The question I would like to raise is whether radiocarbon dating is really more precise, objective and reliable than the traditional way of dating when applied to the problem of the date of the transition from Iron I to Iron IIa. This question is sharpened in light of the fact that the uncertainty in the usual radiocarbon readings (plus or minus 25 years or so) may be as large as the difference in dates in the debate.

The radiocarbon dating has several serious difficulties:

(1) Sample selection. Measuring the remaining carbon-14 content in “long-term” organic samples, such as wood, will provide the date of growth of the tree, rather than the date of the archaeological stratum in which the sample was found. Furthermore, wooden beams were reused in later strata, which can result in even greater differences in date. Since these “long-term” samples may introduce the “old wood” effect, any calculation of precise absolute dates based on “long-term” samples is unreliable and may easily lead to errors of up to several decades or even more. For this reason, researchers prefer to use “short-life” samples, such as seeds, grain or olive pits.

(2) Outliers. In many studies, particular radio-carbon dates are not considered valid because they do not match the majority of dated samples from the site in question. In other words the particular sample is either too late or too early. No doubt the rejection of certain dates as “outliers” and their exclusion from the model may lead to different dates. Omitting outliers would be acceptable only so long as it is being done in a consistent, transparent way.

(3) Calibration. Radiocarbon years differ from calendar years because the former are dependent on the varying content of carbon-14 in the atmosphere. Therefore a complex procedure known as calibration has been developed, which converts radiocarbon test results to calendar years by relating these results to dendrochronologically dated tree-ring samples. The calibration curve is revised periodically as more data are continuously accumulated. But the absolute date after calibration depends on which calibration formula is used. The results, depending on the calibration, can be quite different.

(4) Standard deviation. Radiocarbon dates come with a given uncertainty. This uncertainty ranges from 20 years (for high-precision dating) through intermediate values of 50–100 years, and in some cases up to 100–150 years.