Previous studies of X have not dealt with …
Researchers have not treated X in much detail.
Such expositions are unsatisfactory because they …
Most studies in the field of X have only focused on …
Such approaches, however, have failed to address …
Previous published studies are limited to local surveys.
Half of the studies evaluated failed to specify whether …
The research to date has tended to focus on X rather than Y.
Previously published studies on the effect of X are not consistent.
Smith’s analysis does not take account of …, nor does she examine …
The existing accounts fail to resolve the contradiction between X and Y.
Most studies of X have only been carried out in a small number of areas.
However, much of the research up to now has been descriptive in nature …
The generalisability of much published research on this issue is problematic.
Research on the subject has been mostly restricted to limited comparisons of …
However, few writers have been able to draw on any systematic research into …
Short-term studies such as these do not necessarily show subtle changes over time …
Although extensive research has been carried out on X, no single study exists which …
However, these results were based upon data from over 30 years ago and it is unclear if …
The experimental data are rather controversial, and there is no general agreement about …

The study would have been more interesting if it had included …
These studies would have been more useful if they had focused on …
The study would have been more relevant if the researchers had asked …
The questionnaire would have been more useful if it had asked participants about …
The research would have been more relevant if a wider range of X had been explored

The main weakness with this theory is that …
The key problem with this explanation is that …
However, this theory does not fully explain why …
One criticism of much of the literature on X is that …
However, there is an inconsistency with this argument.
A serious weakness with this argument, however, is that …
One question that needs to be asked, however, is whether …
Smith’s argument relies too heavily on qualitative analysis of …
Smith’s interpretation overlooks much of the historical research …
Many writers have challenged Smith’s claim on the grounds that …
Smith’s analysis does not take account of X, nor does he examine …
It seems that Jones’ understanding of the X framework is questionable.
The existing accounts fail to resolve the contradiction between X and Y.
One of the limitations with this explanation is that it does not explain why…

One major drawback of this approach is that …
Selection bias is another potential concern because …
Perhaps the most serious disadvantage of this method is that …
The main limitation of biosynthetic incorporation, however, is …
Non-government agencies are also very critical of the new policies.
All the studies reviewed so far, however, suffer from the fact that …
Critics of laboratory-based experiments contend that such studies …
Another problem with this approach is that it fails to take X into account.
Difficulties arise, however, when an attempt is made to implement the policy.
Critics have also argued that not only do surveys provide an inaccurate measure of X, but the …
Nevertheless, the strategy has not escaped criticism from governments, agencies and academics.

Critics question the ability of poststructuralist theory to provide …
Non-government agencies are also very critical of the new policies.
Smith’s meta-analysis has been subjected to considerable criticism.
The most important of these criticisms is that Smith failed to note that …
The X theory has been vigorously challenged in recent years by a number of writers.
These claims have been strongly contested in recent years by a number of writers.
More recent arguments against X have been summarised by Smith and Jones (1982):
Critics have also argued that not only do surveys provide an inaccurate measure of X, but the …
Many analysts now argue that the strategy of X has not been successful. Jones (2003), for example, argues that …

Jones (2003) has also questioned why …
However, Jones (2003) points out that …
The author challenges the widely held view that …
Smith (1999) takes issue with the contention that …
The idea that … was first challenged by Smith (1992).
Smith is critical of the tendency to compartmentalise X.
However, Smith (1967) questioned this hypothesis and …
Smith (1980) broke with tradition by raising the question of …
Jones (2003) has challenged some of Smith’s conclusions, arguing that …
Another major criticism of Smith’s study, made by Jones (2003), is that …
Jones (2003) is critical of the conclusions that Smith draws from his findings.
An alternative interpretation of the origins of X can be found in Smith (1976).
Jones (2003) is probably the best known critic of the X theory. He argues that …
In her discussion of X, Smith further criticises the ways in which some authors …
Smith’s decision to reject the classical explanation of X merits some discussion …
The latter point has been devastatingly critiqued by Jones (2003), who argues that …
In a recent article in Academic Journal, Smith (2014) questions the extent to which …
A recently published article by Smith et al. (2011) casts doubt on Jones’ assumption that …
Other authors (see Harbison, 2003; Kaplan, 2004) question the usefulness of such an approach.