What the evidence says
The available evidence on restricting land transfers to outside groups comes almost entirely from one source (Li 2010), a historical-comparative review of colonial land-tenure regimes, supplemented by a single descriptive characterization of Pacific land tenure (Ballard 1997). None of the claims quantify dispossession rates with versus without restriction; all are tier A descriptive historical analyses rather than measured comparisons.
Across three separate colonial contexts, restrictions on transferring land to outside groups did not prevent dispossession of the protected group. In Malaya, the Reservation Enactment restricted land sales to non-Malays, but "many Malays did become landless, and among those who remained on the land, class differentiation proceeded apace." In India, restrictions on tribal land transfers to nontribals "notwithstanding," piecemeal dispossession continued. In British colonial Africa, regulations preventing transfer of tribal land to nontribal hands had what the source calls a "modest" effect on preventing dispossession — a hedged, unquantified characterization rather than a measured near-zero effect.
Sarawak's Native Customary Land restrictions on sales to the Chinese are the one case with a different outcome: mixed evidence rather than no measured effect. The source describes "protection from the risks of the market on one side and exclusion from its benefits on the other" — the restriction shielded land from market-driven loss but also excluded the protected group from market participation and economic opportunity.
Separately, a descriptive characterization of the Pacific region states that foreigners are "generally" excluded from land ownership under both freehold and customary tenure systems. This claim describes the presence of the restriction rather than measuring an outcome from it, is hedged ("generally"), and carries no quantification or timeframe.
No claim in the current sources measures effects on farmland prices, foreign purchase share, domestic farm consolidation, agricultural investment, or production — the outcomes most often associated with contemporary foreign-ownership restrictions on agricultural land. The evidence here is confined to historical dispossession outcomes under colonial-era transfer restrictions.
Where the evidence splits
The Sarawak finding (protection from market-driven dispossession, at the cost of exclusion from market benefits) sits in tension with the Malaya, India, and Africa findings (restriction did not prevent, or only modestly affected, dispossession). The source attributes this difference to tenure design: the Sarawak restriction operated through collective tenure ("Native Customary Land"), which the text explicitly frames as different from the individual-title restrictions used in the other three cases — the source calls Sarawak an example of "the pluses and minuses of collective tenure as a response to piecemeal dispossession." The Malaya, India, and Africa claims do not specify whether their restrictions applied to collective or individual tenure, so it isn't possible to confirm this design difference explains all three of those cases, but it is the explanation the source gives for why Sarawak diverges.