6. Comparison of the Different Ways of Presenting the Pay Gaps
No one measure is appropriate as a single measure of such a complex issue as the gender pay gap. All pay gaps have fundamental differences and limitations relating to their composition and what exactly they represent - there is no ideal option. Public presentations of the pay gap tend to focus on:
1. single headline pay gap figures which do not reveal the particular barriers faced by specific age groups, sectors and occupations and how they are changing
2. the changes from year to year, rather than the longer term trend.
The full-time pay gap is the most commonly cited pay gap and is based on full-time employees only, not including self‑employed. The rationale for focusing on this is to remove any 'distortion' from women being more likely to work part‑time, and the association of part‑time work with lower pay.
But this does not recognise that more women work part‑time in response to greater caring responsibilities and wider barriers to economic progress. These women are not represented in the full-time pay gap.
The overall pay gap includes all full and part-time workers. On the one hand, this does not allow direct comparison of the wages of men and women working full-time. On the other hand, it does capture the effect of factors which result in the channelling of women into part-time work.
The overall pay gap is higher than the full-time gap because:
- A higher proportion of women work part-time - around 41% compared with only 11% of men  .
- Part-time workers of both genders earn less, on average, per hour than full-time workers.
The full-time pay gap removes any influence of different working patterns - in general, part-time work is lower paid per hour. It is arguably, therefore, a better measure for comparison on a like-for-like basis. However, it does not capture wider influences on women's hourly wages. For example, women are more likely to seek part-time work which may be made partly in response to wider societal and economic barriers  .
The overall pay gap captures the effects of all of these barriers but also any 'residual' imbalance between men and women's working patterns relating to preferences rather than barriers.
The part-time pay gap compares only part-time workers. This shows that part-time women have higher part-time wages than part-time men and the pay gap was -7.2% in 2014 in Scotland. However, there are considerable compositional effects due to part‑time workers being predominantly women. A higher proportion of employees working part-time are women (77%) than men (23%)  . Those who work part-time earn less on average than those who work full-time.
Different organisations also emphasise alternative variations of the pay gap based on whether they prefer the median or mean  . The mean pay gap is much more sensitive to very high incomes and is consistently higher than the median. The Scottish Government (and the ONS) emphasises the median pay gap because it is likely to be a better representation of gap in the middle of the earnings distribution. Others emphasise the mean pay gap because it takes into account gender inequalities at the very top of the income distribution.
KEY MESSAGE: the median full-time pay gap is likely to remain the official ONS measure but it is helpful to consider the overall pay gap when discussing wider barriers to economic participation.